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This is to certify that the

thesis entitled

COLLOIDAL PROCESSING OF TITANIUM

DIBORIDE/ALUMINA (TiBz/A1203)
presented by

Lisa Prokurat Franks

has been accepted towards fulfillment
of the requirements for

Master's degree in Materials Science

 

 

and Engineering

   
 

ajor profess

Date August 22, 2001

 

0-7639 MS U is an Affirmative Action/Equal Opportunity Institution

_ .,~ _. _..,..__. ._——_

PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.
MAY BE RECALLED with earlier due date if requested.

 

DATE DUE

DATE DUE

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6101 cICIRCDUoDuost-ms

 

COLLOIDAL PROCESSING OF TITANIUM DIBORIDE/ALUMINA (T iB2/A1203)

By

Lisa Prokurat F ranks

A THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE AND ENGINEERING

Department of Materials Science and Mechanics

2001

ABSTRACT

COLLOIDAL PROCESSING OF TITANIUM DIBORIDE/ALUMINA (TileA1203)
By

Lisa Prokurat Franks

TileA1203 powders produced using self-propagating high-temperature synthesis
(SHS) have been densified using hot pressing and dynamic consolidation techniques, but
the microstructure and phase distribution have been inconsistent. Since the SHS powders
are available commercially, it's possible to also improve green body formation by
controlling interparticle potentials during processing. The interactions between ”KB; and
A1203 have been analyzed with respect to their colloidal properties, as measured by their
respective zeta potentials, density, volume fraction, and particle size. The colloidal
properties and the resulting microstructure of sintered SHS {TiBz/A1203}, with SHS TiBz
in two different aluminas, have been compared. The coagulation behavior of SHS
{TileAlzog} powders was insensitive to colloidal processing, and no matter the
processing condition, the microstructure associated with resistance to ballistic penetration
was present. The coagulation behavior of the SHS TiBz in two different aluminas was
sensitive to colloidal processing, and the SHS TiBz in the Alcoa SG A1203 processed at
pH 7 showed potential to produce the microstructure associated with resistance to

ballistic penetration.

DEDICATION

This work is dedicated to my parents, Mary Pesta Prokurat and Michael A.
Prokurat, whose love, encouragement and support I have always known. Thankfully,
they are of that generation Tom Brokaw has called The Greatest Generation, who know
and teach the value of work, especially that which comes from the labor of one’s own
hands. Any graduate work, especially one that includes laboratory bench work, requires
an integrity, humility, perseverance and patience that I had to have seen and lived with all
these years, to be able to apply to my own work. I will always be grateful for the
sacrifices that gave me, my brother, Rev. Dr. Michael D. Prokurat and my sister, Dr.
Elaine M. Carroll, M.D., opportunities many children only dream about. But my parents’
lasting gift is that basically, they always were, still are, and will always be, just crazy in

love with us.

ACKNOWLEDGMENTS

This study was made possible through the cooperation and support of the Defense
Advanced Research Projects Agency (DARPA), US. Army Tank-Automotive Research
Development and Engineering Center (TARDEC) and Michigan State University under
the Clinton Administration’s Technology Reinvestment Project (TRP).

When one pursues a graduate degree, it is never done alone. When one pursues
an advanced degree as a late vocation while employed full-time, married and a parent,
guidance and support are voluminous and difficult to list completely, however I’d like to
mention specifically:

For inspiring me to climb the mountain: Dr. Gordon Filbey, Dr. William Carson,
Dr. William Gillich, Dr. Andy Niiler and Dr. William Bruchey.

For initiating this program, and opening the doors I needed to get started: Dr.
Ken Oscar, Ms. Pame Watts, Mr. Michael Zapf, Dr. Richard McClelland, Dr. Douglas
Templeton, Dr. Douglas Rose, Dr. Jayaraman, Dr. Larry Drzal and my advisor Dr.
Melissa Crimp.

For getting me past bumps in the road and over the mountain: Dr. Kathryn Logan,
Dr. Douglas Templeton, Dr. Jim Thompson, Dr. Ernest Chin, Mr. Gary Gilde, Dr. Jim
McCauley, Dr. Eldon Case, Dr. Melissa Crimp, Mr. Jeff Swab, Mr. Jack Mullins, Mr.
Patrick Sneary, Mr. Brett Wilson, Mr. Dean Opperman, Mr. Scott Hodges, Mr. Michael
Parham, Ms. Mary Prokurat, Ms. Juliana Franks, Dr. Renate Snider, Dr. Susan Masten,
Mr. Hiroyuki Fukushima, Mr. Yu Liu, Dr. James E. (Ned) Jackson, Ms. Julide Celik, Ms.

Lili Duan, Ms. Xiangshu Jin, Ms. Tara Stabryla, Dr. James Lucas, and Dr. Andre Lee.

For their friendship, inspiration and support during this journey: Ms. Sarah
Newton, Dr. Elaine M. Carroll, Mr. Robert El Henicky, Ms. Elizabeth Davison, Dr.
Roxanne Freedman-Petros, Ms. Kathleen (Kitty) Derbin, Ms. Lee Reimann, J.D., Ms.
Juanita Pipkin, Ms. Beverly K. Sobolewski, Rev. Michael Matsko, and members of the
Great Lakes Chapter of Federally Employed Women (FEW).

Without the love and support of my dear husband David and my sweet daughter

Juliana, I could not have completed this important work, thank you.

TABLE OF CONTENTS

LIST OF TABLES ........................................................................................................... viii
LIST OF FIGURES ............................................................................................................ x
INTRODUCTION .............................................................................................................. 1
1 LITERATURE REVIEW ........................................................................................... 7
1.1 Titanium Diboride (TiBz) — Alumina (A1203) Composites .................................... 7
1.2 Colloidal Processing ............................................................................................... 9
1.2.1 Colloidal Systems ........................................................................................... 9
1.2.2 Particle Description ....................................................................................... l 1

1.3 Derjaguin-Landau-Verwey-Overbeek (DLVO) Theory ....................................... 17
1.4 Hogg, Healy and Fuerstenau (HHF) Theory ......................................................... 18
1.4.1 Development of HHF Theory ....................................................................... 18
1.4.2 Modeling HHF Theory ................................................................................. 21

2 EXPERIMENTAL PROCEDURE ........................................................................... 23
2.1 Starting Powders ................................................................................................... 23
2.1.1 Self-propagating-high-temperamre-synthesis (SHS) TiBz ........................... 23
2.1.2 Alumina (A1203) Powders ............................................................................. 24
2.1.3 SHS COIDpOSItC TIBz/A1203 .......................................................................... 26

2.2 Electrokinetic Sonic Amplitude (ESA) Measurement .......................................... 27
2.3 Stability Predictions .............................................................................................. 28
2.3.1 Hamaker Constant Calculation ..................................................................... 28
2.3.2 Computer Model ........................................................................................... 28

2.4 Slip Preparation and Casting ................................................................................. 29
2.4.1 Electrolyte ..................................................................................................... 29
2.4.2 Slip Suspensions ........................................................................................... 29
2.4.3 Ultrasonication .............................................................................................. 29
2.4.4 Plaster Mold Preparation ............................................................................... 30
2.4.5 Casting .......................................................................................................... 30

2.5 Traditional Binder ................................................................................................. 31
2.6 Cold Isostatic Pressing (CIPing) ........................................................................... 32
2.7 Green Bodies ......................................................................................................... 32
2.7.1 Density Measurement ................................................................................... 32
2.7.2 Binder Burnout and Thermogravimetric Analysis (TGA) ............................ 32
2.7.3 Conductivity Measurement ........................................................................... 3 3

2.8 Pressureless Sintering ........................................................................................... 33
2.9 Sintered Samples ................................................................................................... 34
2.9.1 Density Measurement ................................................................................... 34
2.9.2 Conductivity Measurement ........................................................................... 35
2.9.3 Mounting and Polishing ................................................................................ 35

vi

2.10 Scanning Electron Microscopy (SEM) Observations ....................................... 36

2.10.1 Powders ......................................................................................................... 36
2.10.2 Polished Specimens ...................................................................................... 36
2.11 Microhardness Measurement ............................................................................ 36
3 RESULTS AND DISCUSSIONS ............................................................................. 37
3.1 Properties of TiB2/A1203 Suspensions .................................................................. 3 8
3.1.1 Electrokinetic Sonic Amplitude (ESA) Measurement .................................. 38
3.1.2 Stability Ratio (W) ........................................................................................ 43
3.2 Effect of pH on Green Body Density .................................................................... 46
3.2.1 Material Loss and Sample Attrition .............................................................. 46
3.2.2 Green Body Density Measurements ............................................................. 49
3.2.3 Green Density vs. Cold Isostatic Pressure ................................................... 51
3.2.4 Green Body Conductivity ............................................................................. 51
3.3 Sintered Density .................................................................................................... 52
3.3.1 Binder Burnout and Thermogravimetric Analysis (TGA) ............................ 52
3.3.2 Material Loss and Sample Attrition .............................................................. 54
3.3.3 Sintered Density Measurements ................................................................... 54
3.3.4 Consistency of Sintered Microstructure with Suspension Stabilityc’
Predictions ................................................................................................................. 55
3.3.5 Sintered Sample Conductivity ...................................................................... 65
3.4 Microstructure ....................................................................................................... 65
3.4.1 SHS Composites ........................................................................................... 65
3.4.2 SHS TiBz / A1203 Composites ...................................................................... 65
3.5 Microhardness Measurement ................................................................................ 66
4 CONCLUSIONS ....................................................................................................... 67
5 FUTURE WORK ...................................................................................................... 70
REFERENCES ................................................................................................................. 71
APPENDICES .................................................................................................................. 78
A. Equations for Evaluating Armor Efficiencies ............................................................. 79
B. Electrokinetic Sonic Amplitude 038A) Measurements .............................................. 82
C. Green Body Density Measurements ........................................................................... 94
D. Sintered Density Measurements ............................................................................... 100
E. Conductivity Measurements ..................................................................................... 102
F. Microhardness Measurements .................................................................................. 104
G. Porosity Measurements fi'om Backseatter SEM Micrographs ........................... 106

vii

LIST OF TABLES

Table 1: Physical properties reported by the manufacturer for SHS powders, TiB2 and

Composite {TiBz/A1203} ........................................................................... 24
Table 2: The chemical and impurity analysis and physical properties for AKP-50 A1203
reported by the manufacturer ..................................................................... 25
Table 3: The chemical and impurity analysis and physical properties for Alcoa-SG A1203
reported by the manufacturer ..................................................................... 26
Table 4: Ceramic properties for Alcoa-SG A1203 reported by the manufacturer ......... 26
Table 5: The calculation of the Hamaker constant (A,-) in a vacuum [Bleier, 1983] where
A,(kT) ~ 113.7{(e3-1)2/[( e. +1)3’2(e. +2)"2]} ................................................... 28
Table 6: Binder burnout schedules for PEG processed samples ............................ 33
Table 7: Pressureless Sintering schedules for all samples .................................... 34
Table 8: Hand polishing papers for sample preparation in the order used .................. 3 5

Table 9: Relative stability between SHS TiB2 and AKPSO A1203 predicted by Suspension
Stabilityg ............................................................................................. 44

Table 10: Relative stability between SHS TiB2 and Alcoa-SG A1203 predicted by
Suspension Stability‘D .............................................................................. 45

Table 11: Summary of processing conditions chosen for the three composite systems
investigated .......................................................................................... 45

Table 12: Material loss during green body forming for each composite recipe and
processing pH ....................................................................................... 46

Table 13: Sample attrition during green body forming for each composite recipe and
processing pH ........................................................................................ 48

Table 14: Evaluation of sintered microstructure for consistency with processing
behaviors ............................................................................................. 56

Table 95: Potentiometric Titration (POTN729.esa), 0.5 vol. % TiB2, 1x10'4 M KN03. ..83
Table 16: Potentiometric Titration (POTN733.esa), 0.5 vol. % TiB2, 1x10'3 M KNO3. ..84

Table 17: Potentiometric Titration (POTN73 1 .esa), 0.5 vol. % TiB2, 1x10’2 M KN03. . .85

viii

Table 18: Potentiometric Titration (POTN717.esa), 0.5 vol. % AKP-SO A1203, 1x104 M

KN03 ................................................................................................. 86
Table 19: Potentiometric Titration (POTN719.esa), 0.5 vol. % AKP-SO A1203,1x10'3 M
KNO3 ................................................................................................. 87
Table 20: Potentiometric Titration (POTN723.esa), 0.5 vol. % AKP-SO A1203, 1x1 0'2 M
KNO3 ................................................................................................. 88
Table 21: Potentiometric Titration (POTN710. esa), 0. 5 vol. % Alcoa SG A-1000 A1203,
1x104 M KNO3 ...................................................................................... 89
Table 22: Potentiometric Titration (POTN713.esa), 0.5 vol. % Alcoa SG A-1000 A1203,
1x10'3 M KNO3 ...................................................................................... 90
Table 23: Potentiometric Titration (POTN725.esa), 0.5 vol. % Alcoa 80 A-1000 A1203.
1x10'2 M KNO3 ...................................................................................... 91
Table 24: Potentiometric Titration (POTN702. esa), 0. 5 vol. % SHS Composite
{TiB2/A1203},1x10'3M KN03 .................................................................... 92
Table 25: Potentiometric Titration (POTN705. esa), 0. 5 vol. % SHS Composite
{TiB2/A1203}, 1x10'3 M KN03 .................................................................... 93
Table 26: Green Body Density Data and Calculations for SHS TiB2/AKP 50 A1203
Ceramic Composites ................................................................................ 95
Table 27: Green Body Density Data and Calculations for SHS TiB2/Alcoa SG A-1000
A1203 Ceramic Composites ........................................................................ 96
Table 28: Green Body Density Data and Calculations for SHS TiB2/A1203 Ceramic
Composites ........................................................................................... 98
Table 29: Sintered Density Measurements for the Three Composite Systems

Investigated ......................................................................................... 101
Table 30: Conductivity Measurements ......................................................... 103
Table 31: Microhardness Measurements (V ickers (HV)) .................................... 105
Table 32: Porosity Measurements from Backseatter SEM Micrographs .................. 108

Table 33: Summary of Lineal Analysis Data for Porosity Measurements from Backseatter
SEM Micrographs .................................................................................. 112

ix

LIST OF FIGURES

Figure 1: The microstructure termed “continuous” and more penetration resistant, taken
from Logan [1997]. Light areas are TiB2 and dark areas are A1203 ........................... 8

Figure 2: The microstructure termed “discontinuous” and less penetration resistant, taken
from Logan [1997]. Light areas are TiB2 and dark areas are A1203 ........................... 9

Figure 3: Surface charge influence on the distribution of nearby ions in the polar medium,
after Shaw [1992, p. 178] ........................................................................... 12

Figure 4: Potential energy of the diffuse electrical double layer, after Shaw [1992, p.
178] .................................................................................................... 13

Figure 5: Representation of the electrical double layer according to Stern's theory, after
Shaw [1992, p. 183] and Heimenz [1997, p. 541] .............................................. 14

Figure 6: Potential of the electrical double layer according to Stern's theory, after Shaw
[1992, p. 183] and Heimenz [1997, p. 541] ...................................................... 14

Figure 7: Total potential energy of interaction (VT) between two particles as function of
their separation, after Hogg et a1. [1966] ......................................................... 18

Figure 8: Geometrical representation of the interaction between two dissimilar spherical
particles of radii a, and a; as two infinitesimally small, flat plates where h<<a, and h<<
02, afier Hogg et al [1966] .......................................................................... 19

Figure 9: Zeta potentials determined from ESA data collected using the Matec ESA 8000
for AKP-SO A1203 suspended in three different concentrations of electrolyte .............. 38

Figure 10: Zeta potentials determined from ESA data collected using the Matec ESA
8000 for Alcoa SG A-1000 A1203 suspended in three different concentrations of
electrolyte ............................................................................................. 39

Figure 11: Zeta potentials determined from ESA data collected using the Matec ESA
8000 for SHS TiBz suspended in three different concentrations of electrolyte ............. 39

Figure 12: Zeta potentials for each starting powder suspended in 1x10'3 M electrolyte
from ESA data collected using the Matec ESA 8000 .......................................... 40

Figure 13: Stability ratio data prepared from the computer program, Suspension
Stability", for SHS TiB2 and AKP 50 A1203 .................................................... 43

Figure 14: Stability ratio data prepared from the computer program, Suspension
Stabilityo, for SHS TiB2 and Alcoa-SO A-l ooo A1203 ........................................ 44

Figure 15: Green density vs. processing pH for each composite recipe ..................... 50

Figure 16: Green density vs. pressure applied to composite samples during cold isostatic
pressing ............................................................................................... 51

Figure 17: Thermogravimetric analysis (TGA) for the SHS TiB2 — AKP 50 A1203
composite green samples prepared with a traditional binder; the 2 wt% polyethylene
glycol (PEG) binder was removed by binder burnout before Sintering ...................... 52

Figure 18: Thermogravimetric analysis (TGA) for the SHS TiB2 — Alcoa SG A1203
composite green samples prepared with a traditional binder; the 2 wt% polyethylene
glycol (PEG) binder was removed by binder burnout before Sintering ...................... 53

Figure 19: Thermogravimetric analysis (TGA) for the SHS {TiB2/A1203} composite
green samples prepared with a traditional binder; the 6 wt% polyethylene glycol (PEG)
binder was removed by binder burnout before Sintering ....................................... 53

Figure 20(a): Sintered density (g/cc) vs. processing condition for each composite
recipe .................................................................................................. 54

Figure 20(b): Sintered density (% Theoretical) vs. processing condition for each
composite recipe .................................................................................... 55

Figure 21: Backseatter scanning electron micrographs (20.0 kV) of the microstructures of
each of the three composite systems at the four processing conditions; markers are 100

pm in every micrograph; white areas are the TiB2, gray areas are the A1203, and black
areas are pores ....................................................................................... 57

Figure 21(a): Backseatter scanning electron micrograph (20 kV) of SHS composite
{TiB2/A1203} processed with PEGZOM binder; marker (white line at bottom of
micrograph) is 100 um; white areas are the TiB2, gray areas are the A1203, and black
areas are pores ....................................................................................... 58

Figure 21(b): Backseatter scanning electron micrograph (20 kV) of SHS composite
{TiB2/A1203} processed at pH 4; white areas are the TiB2, gray areas are the A1203, and
black areas are pores ................................................................................ 58

Figure 21(c): Backseatter scanning electron micrograph (20 kV) of SHS composite
{TiB2/A1203} processed at pH 7; marker (white line at bottom of micrograph) is 100 um;
white areas are the TiB2, gray areas are the A1203, and black areas are pores .............. 59

Figure 21(d): Backseatter scanning electron micrograph (20 kV) of SHS composite

{TiB2/A1203} processed at pH 9; marker (white line at bottom of micrograph) is 100 um;
white areas are the TiB2, gray areas are the A1203, and black areas are pores .............. 59

xi

Figure 21(c): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/AKP 50
A1203 processed with PEGZOM binder; white areas are the TiB2, gray areas are the A120 3,
and black areas are pores ........................................................................... 60

Figure 21(i): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/AKP 50
A1203 processed pH 4; white areas are the TiB2, gray areas are the A1203, and black areas
are pores .............................................................................................. 60

Figure 21(g): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/AKP 50
A1203 processed pH 7.5; white areas are the TiB2, gray areas are the A1203, and black
areas are pores ....................................................................................... 61

Figure 21(h): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/AKP 50
A1203 processed pH 8; white areas are the TiB2, gray areas are the A1203, and black areas
are pores .............................................................................................. 61

Figure 21(i): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/Alcoa 80
A1203 processed with PEGZOM binder; marker (white line at bottom of micrograph) is
100 um; white areas are the TiB2, gray areas are the A1203, and black areas are pores. . .62

Figure 210): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/Alcoa 80
A1203 processed at pH 4; marker (white line at bottom of micrograph) is 100 um; white
areas are the TiB2, gray areas are the A1203, and black areas are pores ..................... 62

Figure 21(k): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/Alcoa SG

A1203 processed at pH 7; marker (white line at bottom of micrograph) is 100 um; white
areas are the TiB2, gray areas are the A1203, and black areas are pores ..................... 63

Figure 21(1): Backseatter scanning electron micrograph (20 kV) of SHS TiB2/Alcoa 80
A1203 processed at pH 8; marker (white line at bottom of micrograph) is 100 um; white
areas are the TiB2, gray areas are the A1203, and black areas are pores ..................... 63

Figure 22: Scanning Electron Microscope (SEM) image of SHS {TiB2/A1203} composite
powder dusted onto carbon tape; the large charging particles were thought to be the non-
conducting A1203 and the small particles were thought to be the conducting TiB2; recent
investigations [Wilson, 2001] indicate most particles are a mixture of both the TiB2 and
the A1203 ............................................................................................. 64

Figure 23: Backseatter SEM micrograph with lineal analysis, after EMSE
[1986, p. 3832] .................................................................................... 107

xii

Introduction

The skin, structure, or add-on module that protects military vehicles against
bullets, shells or other projectiles, is armor. In the past, the most capable armor was
heavy and developed for main battle tanks weighing 50 tons or more. The increasingly
changing state of global politics requires rapid deployment of a military force anywhere
in the world. Rapid deployment dictates that the best armor be available for lightweight
military vehicles.

Since the material used in fabricating the first armors was steel, the effectiveness
of other armor material is compared to the first rolled homogeneous steel armor referred
to as RHA. The protective ability of armor is characterized by its ballistic performance,
which is quantified by its mass efficiency, a dimensionless factor that compares the areal
density (mass/area) of an alternate armor material or system to RHA. For example, the
typical specification of the material used to construct a lightweight military vehicle to
provide protection against 7.62 mm armor piercing bullets at point blank range, is steel
having an areal density of about 114 ltg/m2 [0gorkiewicz, 1995]; the mass efficiency at
this specification would therefore be 1.0 [Woolsey et al., 1989; see also Appendix A].

Hardening steel increases its effectiveness by enabling it to break the bullet or
projectile more efficiently, but hardening also increases residual stresses making the
hardened steel more prone to cracking. Dual hardness armor consists of two different
steels roll-bonded together and heat treated to give the outer layer high hardness while the
inner layer remains softer but tougher; dual hardness armor can have a mass effectiveness

of as much as 1.78 [0gorkiewicz, 1995]. Although the combination of a hard outer layer

with a softer inner one obviously improves ballistic performance, the weight of steel has
a negative impact on the speed and transportability of a military vehicle.

Aluminum (Al) is used successfully as a structural material for military vehicles
[Haworth, 1999, pp. 28, 95] as it has less weight and the ability to absorb the kinetic
energy of projectiles. An Al inner structure with a high hardness steel outer plate is
widely employed as ballistic protection for light armored vehicles; this dual hardness
armor has a mass effectiveness of between 1.2 and 1.3 against 7.62 mm armor piercing
bullets [0gorkiewicz, 1995]. However, when weight is considered as a factor, even
harder, non-metallic materials, namely ceramics, afford the best protection [Callister,
2000, p. 441]. The most common metal-non-metallic armor system is Al faced with tiles
of aluminum oxide (A1203) [0gorkiewicz, 1995]. This dual metal-ceramic system has a
mass effectiveness ranging from 2.2 to 2.7 against 7.62 mm armor piercing bullets
[0gorkiewicz, 1995] and can have a weight saving of 60% [Hetherington, 1995] when
compared with RHA. Other ceramics such as boron carbide (B4C), silicon carbide (SiC)
and titanium diboride (TiB2) are even more effective [Hohler et al., 1995], but also more
costly.

An A1203 based armor system is advantageous. A1203 is a sintered, rather than
hot-pressed, component of armor, and because of its large demand by the A1 industry
[EMH Vol. 4, 1991, p. 50], is inexpensive as compared to 34C, SiC and TiB2. A1203, no
matter the type, resists penetration linearly as tile thickness increases (0 to 30 mm)
[Strassburger et al., 1995]. Its mechanical properties can be improved by the addition of

a second phase of small, dispersed, non-equiaxed TiB2 particles [Liu and Ownby, 1991].

The high cost of TiB2 powders stems from its energy intensive processing via
carbotherrnal reduction [EMH Vol. 4, 1991, p.48]. Fuel costs are high to reach the
temperatures required for TiB2 production. An alternate synthesis route is via a particular
form of combustion termed self-propagating-high-temperature-synthesis (SHS)
[Merzhanov, 1990, pp. 1-3]. SHS is an instantaneous event rather than a long-term, high-
temperature reaction as is carbothermic reduction. SHS thereby eliminates high fuel
costs, and also incidentally increases the purity of the resulting powders. Logan [Ph.D.
Thesis, 1992] is able to produce not only TiB2 powders by SHS, but also the composite
titanium diboridelalurnina (TiB2/A1203) powder.

TiBZ/A1203 powders produced by SHS have been hot pressed into armor tiles that
exhibit superior resistance to penetration as compared to TiB2, SiC, 84C or A1203 [Logan
Ph.D. Thesis, 1992]. As with other advanced ceramics, however, difficulties in
processing TiB2/A1203 arise from the inability to reproduce specimens with consistent
microstructure and properties [Lange, 1989]. Commercial availability of SHS TiB2 and
SHS {TiB2/A1203} powders makes it possible to investigate alternative processing
methods that may reduce the range and variation of properties of TiB2/A1203 armor tiles.
An additional consideration is that any alternative processing method should be low cost.

The unique feature of SHS-produced starting powders is that the combination
reaction is self-sustaining [Hoke and Meyers, 1995]. Upon lowering the free energy of
the starting materials, the energy released to the products typically raises the temperature
of the products. Many contaminants (oxygen, nitrogen, etc.) that may exist on the
starting powders volatize and leave behind escape paths in the freshly synthesized

material. These escape paths, combined with a typical volume decrease during reaction

and the initial porosity of the reacting mixture, produce a material with 40-50% residual
porosity. Hoke and Meyers [1995] suggest that densification can best be achieved by
“forced consolidation” techniques that occur over small time scales immediately
following combustion synthesis. In contrast to conventional consolidation of ceramic
powders such as hot pressing or hot isostatic pressing, which are time-consuming and
slow, forced consolidation is a rapid technique.

Kecskes and others [1996] applied forced consolidation, termed dynamic
consolidation (DC) techniques, to TiB2/A1203 powders immediately afier their synthesis
by SHS. In DC, a powdered amatol explosive (80/20 NHaN03/TNT) drives two high-
hardness steel compression plates (Brinell Hardness of 480-530) containing the SHS
reacted product to effect consolidation. However, the large differences between the
melting point of the TiB2 and A1203 phases, and the susceptibility of densified samples to
contamination (from the surrounding insulating media and sand) have limited the success
of DC [Kecskes et al., 1996].

Ultimately, the advantages of combining SHS and DC techniques will be to
eliminate the demands of conventional green body formation, that is mixing, shaping,
drying and firing, all of which are labor-time-cost-intensive steps in ceramic processing.
With the commercial availability of inexpensive SHS products such as TiB2 and

TiBz/AlZO3 powders, and the current lack of large-scale success with DC, other

conventional processing techniques should be considered. Particularly, processing steps
that control green body formation as well as densification should be investigated. One of
the potentially most viable alternatives is colloidal processing [Lange, 1989; Wilson and

Crimp, 1993].

After the commercial powders have been synthesized, they are mechanically
mixed (e.g. by ball milling) to optimize particle size and the range of particle-size
distribution in the SHS powders. However, only chemical mixing (colloidal processing)
can improve processing reliability and therefore provides more consistent ceramics
[Lange et al., 1990]. Wilson and Crimp [1993] have modeled the colloidal processing of
ceramic composites based on the approximations developed by Hogg, Healy and
Fuerstenau (HHF). The model, Suspension Stability©, uses measurable material data to
create information to predict the coagulation state of two component colloidal
suspensions.

The colloidal processing of TiB2/A1203 composites, both the SHS produced
composite and composites mixed from other readily available commercial aluminas with
the SHS produced TiB2, will be investigated.

The objectives of this investigation were to:

0 show that the model, Suspension Stability© [Wilson and Crimp, 1993], developed to
predict coagulation behavior based on the Si3N4/SiC composite system, will predict
the coagulation behavior of the TiB2/A1203 composite system.

0 show that colloidal processing will reproduce the microstructure obtained by Logan
[1997] in TiB2/A1203 composites associated with penetration resistance in ceramic
armor.

0 measure the zeta potential (Q) for SHS TiB2, Sumitomo AKPSO A1203, Alcoa
Superground A-1000 A1203 and Composite SHS {TiB2/A1203},

0 predict the coagulation behavior of the TiB2 - A1203 ceramic composite system in

suspension using the model Suspension Stability© [Wilson and Crimp, 1993].

slip cast 30/70 wt. % TiB2/A1203 suspensions at conditions for coagulation,
heterocoagulation and dispersion behavior based on these predictions.
free-sinter the slip cast TiB2/A1203 samples to maximum densification.
measure the density of the slip cast TiB2/A1203 samples in the green and sintered
states.
measure the microhardness of the sintered TiB2/A1203 samples.
examine the microstructure of the TiB2/A1203 samples and compare to the
o predictions for coagulation, heterocoagulation and dispersion behavior of the
TiB2 and A1203, and
o microstructures of samples prepared by Logan [1997] associated with

penetration resistance in ceramic armor.

1 Literature Review

The recent and relevant literature for ceramic armor performance, colloidal
systems with emphasis on particle interactions, and theories of colloidal stability was

reviewed to understand:

0 the desired microstructure for titanium diboride-alumina ceramic composites for

penetration resistance, and
o the predictive basis of the computer model used to establish conditions for colloidal

processing of the titanium diboride-alumina powders.

1. 1 Titanium Diboride (T 1'82) - Alumina (Al203) Composites

Titanium diboride (TiBz), silicon carbide (SiC), boron carbide (B4C), and alumina
(A1203) perform well as armor materials, but TileAIZO3 composites have superior
resistance to penetration [Logan Ph.D. Thesis, 1992]. Composite TileAIZO3 powders
made by self-propagating high temperature synthesis (SHS) and then immediately hot
pressed into armor tiles demonstrate a superior resistance to the high strain rate

penetration required for armor [Abfalter et al., 1992]. Analysis of TileA1203 targets

indicate a bias in the microstructure of the penetration resistant targets [Logan, 1997].

Superior performance is associated with a “continuous” microstructure where the TiB2
forms an interconnecting network at the A1203 grain boundaries. Targets where the TiB2
is distributed in the A1203 grains, termed “discontinuous,” lack the same penetration
resistant performance [Logan, 1997]. According to Logan [1997], the term continuous

describes TiB2 surrounding the A1203 grains, forming an unbroken, interconnected,

electrically conductive TiB2 network in the target (Fig. l), and discontinuous describes
TiB2 dispersed in A1203 grains forming a more homogenous though electrically non-
conductive target (Fig. 2). Although much work has been done to refine the process for
synthesizing the composite TiB2/A1203 powders and define the properties of the hot
pressed, ceramic composites, there has been no alternative processing of the powders to
improve the reproducibility of TiB2/A1203 armor tiles. One of the potentially most viable

alternatives is colloidal processing [Lange, 1989; Wilson and Crimp, 1993].

 

Figure l: The microstructure termed “continuous” and more penetration resistant,
taken from Logan [1997]. Light areas are TiB2 and dark areas are A1203.

 

Figure 2: The microstructure termed “discontinuous” and less penetration resistant,
taken from Logan [1997]. Light areas are TiB2 and dark areas are Al203.

1.2 Colloidal Processing

1.2.1 Colloidal Systems

1.2.1.1 Colloidal Suspensions

Colloidal suspensions form when an insoluble substance is broken down into very
small particles (disperse phase) and distributed more or less uniformly through another
substance (dispersion medium), regardless of the state of the matter [Hunter, 1993, p.2].
A sol is the specific name for the particular suspension of a solid disperse phase in a
liquid dispersion medium [Takeo 1999, p. 5]. Another designation for a sol is lyophobic,
or solvent-hating, colloid [Becher, 1990, p. 95]. Sols are distinguished from true
solutions by the size of the particles: one nanometer or less for solute and solvent in a
solution, and one nanometer to one micron (or more) for the dispersed phase of a sol
[Hunter, 1993, p. 2]. In a typical sol, the dispersed phase is much larger than the

molecules of the liquid medium.

1 .2.1.2 Coagulation

The challenge in forming colloidal suspensions is controlling aggregation, which
is also termed coagulation or agglomeration [Hunter, 1993, p. 7]. The colloid suspension
forms through distribution of the disperse phase in the dispersion medium while
maintaining a discrete nature for the particles of the disperse phase [Hunter, 1993, p. 2].
A colloidal system, consisting of the particles, the liquid and any electrolytes present in
the liquid, has the important feature of a large ratio of surface area to volume of the
dispersed solid [Takeo, 1999, p. 1] such that the area of contact between the dispersed
particles and the dispersion medium is relatively large. The energy associated with
creating and maintaining that interface can be significant and depends on its fundamental
chemistry. The total free energy of a colloidal system can always be lowered by a
reduction in the interfacial area, i.e., coagulation or agglomeration, which is controlled by
the electrostatic character of the particle-liquid interface. Attractive and repulsive

electrostatic forces dictate the rate of coagulation [Hunter, 1993, p. 98].

1.2.1.3 Colloidal Forces

Particles in a colloidal suspension come together because of attractive van der
Waals forces. For covalently bonded ceramic materials, “London forces” explain almost
all of the van der Waals attraction [Shaw, 1992, p. 216]. London [1930, as cited in Shaw,
1992, p. 215] explained that attraction between molecules is due to the polarization of
one molecule by fluctuations in the charge distribution in a second molecule, and vice
versa. This attractive energy is very short-range and additive; it varies inversely with the
sixth power of the interparticle distance, and can be computed by summing the attractions

between all interparticle pairs [Shaw, 1992, p. 216]. Hamaker [1937, as cited in Shaw,

10

1992, p. 216] derived an expression for the London interaction energy (VA) for the case of
two spherical particles of radii a; and a; separated in a vacuum by a shortest distance H,

wherex=H/(a,+a2)andy=a,/a2:

 

 

2
Vivi 2 y + 2 y +21n f ”y” (1)
12 x +xy+x x +xy+y x +xy+x+y

A is the Hamaker constant. Bleier (1983) calculated the Hamaker constant in a vacuum

using a simplified Lifshitz method:

(63-1)2
(9: +1)3/2(ei + 2)1/2

 

A,(kT) s 113.7 (2)

Particles in a liquid, rather than a vacuum or air, have a considerably lower London - van
der Waals interaction energy [Shaw, 1992, p. 217]. For two different particles in a liquid
medium, an effective Hamaker constant is used [Shaw, 1992, p. 218]:

Aerr= (All/2 - Ami/2) (Ajm _Am1/2 (3)
To consider other forces in a colloidal suspension, a detailed description of the particles

themselves is needed.

1.2.2 Particle Description

1.2.2.1 Surface Charge of Particles

Generally, particles develop a surface charge when in contact with a polar, liquid
medium. The origin of this surface charge may be ionization, ion adsorption or ion
dissolution [Shaw, 1992, p. 174]. The surface charge affects the distribution of ions in

the immediate vicinity of the particle (Fig. 3).

11

6
GB 9 69 e
e
e 6613 GB
6
69 e e 69
e
I I lCo-ions
Counter-ions
Particle Surface
Surface Charge

Figure 3: Surface charge influence on the distribution of nearby ions in the polar
medium, after Shaw [1992, p. 178].

If the charged particle surface is considered a plane carrying a uniformly distributed
charge, then, applying Boltzmann ’3 distribution law, the electrical potential (w) decreases
exponentially with distance from the surface:
1;! = 1/10 exp(—xz) [Everett, 1988, p. 42] (4)

where W is the electric potential at the surface and z is a measure of distance. At a
distance 1/ K the potential drops by a factor of l/e (Fig. 4). The influence of charge from
the particle surface and the mixing tendency of thermal motion lead to the formation of
an electrical double layer [Shaw, 1992, p. 174]. The parameter III: is also a measure of

the thickness of the electrical double layer [Everett, 1988, p. 42] taken from:

2 = Bavze’NAC

-2
lOOOatT (cm ) (5)

where v is the counter-ion valence, e is the electronic charge, It is Boltzmann’s constant, T
is temperature, C is electrolyte concentration, NA is Avagadro’s number, and a is the

dielectric constant [Texter, 2000]. Figure 4 denotes the simple case of a particle in a

12

medium with no adsorbed surface-active ions or polyvalent counter ions present so that
as the distance from the charged particle surface increases, the potential energy decreases,

and 1h: defines the ionic atmosphere [Everett, 1988, p. 42].

Potential (yr)

 

1
UK
Distance (x)

 

Figure 4: Potential energy of the diffuse electrical double layer, after Shaw [1992, p.
178].

1.2.2.2 Electrical Double Layer

The electric double layer is the charged particle surface and the neutralizing
excess of counter-ions over co-ions diffused in the liquid polar medium [Shaw, 1992, p.
174]. The variation in ion density near the particle interface with the liquid polar medium
may be further subdivided into two phases that carry equal and opposite charge
[Hiemenz, 1997, p.499]. Stern [1924, as cited in Shaw, 1992, p. 182, or Heimenz, 1997,
p.527] proposed that these two phases (inner and outer parts of the double layer) are

separated by a plane (surface) referred to as the Stern plane or surface (Fig. 5).

13

  

 

111., e,

hear

arttcln Sung:

Figure 5: Representation of the electrical double layer according to Stern's theory,
after Shaw [1992, p. 183] and Heimenz [1997, p. 541].

The Stern surface lies at a distance 6 from the particle surface. Outside the Stern surface,

the surface potential decreases exponentially (Fig. 6).

W0

  
 
   
  

V’s Zeta potential

Potential

wd Potential at the diffuse
' double layer boundary

 

 

 

5 UK Distance

Figure 6: Potential of the electrical double layer according to Stern's theory, after
Shaw [1992, p. 183] and Heimenz [1997, p. 541].

14

When adsorbed surface-active ions or polyvalent counter-ions are present, the Stem
surface potential may change sign or intensity. Applying Stern theory quantitatively to
determine potential is problematic because parameters such as 1y; cannot be assessed
experimentally [Heimenz 1997, p. 529]. However, the potential in the diffuse double
layer can be measured near the inner limit ( V10), which is either the actual surface or the
Stern surface, and is called the zeta potential (C) [Heimenz 1997, p. 529; Everett, 198 8,

p. 90].

1.2.2.3 Zeta (Q) Potential

The “boundary” between the Stern layer and the diffuse layer is a surface where
movement between the particle with its adsorbed ions and the liquid medium occurs.
This boundary is referred to as a hydrodynamic slip plane or plane of shear; the zeta (Q)
potential is defined at this boundary [Heimenz p. 541; Everett, p. 90]. Electrokinetic
phenomena, that is, electrophoresis, electroosmosis and streaming potential, can be
measured experimentally to determine the potential in the double layer near the charged
surface [Heimenz 1997, p. 534]. Electrophoresis has the greatest practical applicability
of these electrokinetic phenomena [Shaw, 1992, p. 190]. Interpreting these
measurements yields the zeta potential (Q). Although electrophoresis has long had the
greatest practical applicability of these electrokinetic phenomena [Shaw, 1992, p.190],
electrokinetic sonic amplitude (BSA) is one of the most practical and repeatable tools for

obtaining zeta potential (C) data [Hunter, 1993, p. 382; Wilson and Crimp, 1993].

15

1.2.2.4 Electrokinetic Sonic Amplitude (ESA)

ESA is a patented method to measure electrokinetic properties without the
limitations and restrictions of traditional microelectrophoresis technique [Matec, 2001].
Specifically, ESA is an electroacoustic method whereby a high fi‘equency electric field is
applied to the colloidal suspension. When the particles move (electrophoretically) in the
applied field, if there is a difference in density between the particles and the liquid, the
motion of the particles produce an alternating acoustic wave called the electrokinetic
sonic amplitude (BSA). The measure of BSA is in pressure amplitude per unit of applied
electric field (BSA ((0)), and is used to determine the ESA dynamic mobility (ad ((0)) by

the following equation [O’Brien, 1986 &1990, as cited in Wilson and Crimp, 1993]:

ESA(a))
. = —— 6
,. (w) H ( >

where ¢ is the volume fraction of solids, Ap is the density difference of the particles and
the liquid, and c is the velocity of sound in the suspension. The ESA dynamic mobility is
used to determine the zeta potential (Q) by the equation [O’Brien, 1986 & 1990, as cited
in Wilson and Crimp, 1993]:

c=[M]G(a)-' (7)

80 gr

where n is the viscosity of the suspension, 308, is the applied electric field, and G (01)" is
the correction for the inertia of the particle in an alternating field. Using a Matec ESA-
8000 system to collect ESA data, the pH, conductivity and temperature can also be

measured concurrently [Matec, 2001] to employ zeta potential (Q) in the application of

16

theories of colloidal stability to ceramic composite suspensions [Wilson and Crimp,

1993].

1.3 Derjaguin-Landau- Verwey-Overbeek (DL V0) Theory

The forces that arise between similar particles in aqueous media are described by
the classical DLVO theory of the stability of lyophobic colloids [Colic et al., 1997].
According to DLVO theory, the total interaction energy between two particles (VT) is
obtained by summing the interaction energies due to the van der Waals attraction (VA)
and the electrostatic double layer repulsion (VR):

V, = V A + VR (8)
When two particles are forced together, their respective diffuse layers overlap, increasing
the concentration of counterions between them and giving rise to an osmotic pressure,
and thus a repulsive force [Colic et al., 1997]. However, most ceramic composite
systems are made up of dissimilar rather than similar particles, and the theoretical
analysis of the interaction of dissimilar double layers using DLVO theory requires
tedious graphical or numerical integrations [Derjaguin (1954) and Devereux and de
Bruyn (1963), as cited in Hogg et al., 1966]. Therefore, another quantitative theory that
can better describe the kinetics of coagulation for a ceramic composite colloidal system is

needed.

17

1.4 Hogg, Healy and Fuerstenau (HHF) Theory
1.4.1 Development of HHF Theory

1.4.1.1 Colloidal Particle Interactions

Hogg et a1. [1966] derived a relationship to describe the potential energy of
interaction between the dissimilar electrical double layers associated with the particles in
a multicomponent colloidal system. As in DLVO theory, the total potential energy of
interaction is generally given by equation (8), and when the surface potentials of the two
interacting particles are large and have the same sign, then V3 is positive and the total

energy VT passes through a maximum (Fig. 7).

 

15

 

 

 

 

O
=
Barrier to
Coagulation

 

 

Total Potential Energy of Interaction (VT)

15 i '7
Separation Distance (KI-Io)

Figure 7: Total potential energy of interaction (Vr) between two particles as
function of their separation, after Hogg et al. [1966].

18

The potential energy of the attractive forces (VA) is as in equation (1). Hogg et a1. [1966]
expanded the expression for the potential energy of the repulsive forces (VR), however, by
treating the interaction between small electrical double layers on spherical particles after
Derjaguin [1934, as cited in Hogg et al., 1966]. The interaction is then as infinitesimally

small parallel rings, each of which can be considered as a flat plate (Fig. 8) so that:

V =£alaz(V/20,+l/Izo,[ ZWOIV’O, h[l+exp(-KHO)

R 4(01 4’"2) 6’20. +V’202) l-eXp(- x110 )]+ln(1 -exp(- 260)] (9)

where e is the dielectric constant, a] and a; are the particle radii, w is the particle surface

potential, K is the Debye-Hiickel parameter, and H0 is the particle separation distance

[Hogg et al., 1966].

 

Figure 8: Geometrical representation of the interaction between two dissimilar
spherical particles of radii a; and a; as two infinitesimally small, flat plates where
h<<a, and h<< 02, after Hogg et a1 [1966].

19

However, the variation in VT, that is, the height of the barrier to coagulation (Fig. 7),
affects the rate of coagulation [Hogg et al., 1966]. When the energy of interaction
between the particles is zero, except for an infinite attraction when the particles are in
contact, the sol is under rapid coagulation conditions [Smoluchowski (1916, 1917), as
cited in Hogg et al., 1966]. When V1 is not zero, the frequency and types (between like

or unlike) of collisions between particles will describe the overall rate of coagulation.

1.4.1 .2 Coagulation Kinetics
When two particles collide, they stick together and fall out of suspension
(coagulate); the frequency of collisions between particles determines (J), the rate of

coagulation [Smoluchowski (1916, 1917), as cited in Hogg et al., 1966] so that:

_ dvo
dt

J = = 87rDv02R0 (10)

 

where Va is the number of particles, D is the diffusion coefficient and R0 is the minimum
separation of particles. Where there are energy barriers between the particles, the rate of

coagulation is reduced by a factor W [Fuchs (1934), as cited in Hogg et al., 1966] so that:

2
J =L’IQVF3_R_0 (11)
But Wis given by:
°° 1V dR
W =R0R-[6kafi F (12)

 

Specifically, W denotes the ratio of rapid to slow coagulation [Hogg et al., 1966].

20

Under conditions where the energy of interaction between the particles is not zero, the
probability that particles of types i and j collide is reduced by a factor Wij [Hogg et al.,

1966]:

°° V,” dS
Wij =ZICXp[—£F]§-2— (13)

Where SER/é' and éfia) + (1,). The overall stability ratio (WJ for a suspension containing
two kinds of particles (1 and 2), however, is dependent upon their probabilities of
interaction [Hogg et al. 1966]. Probabilities of interaction for particles 1 and 2 between
like (P11, P22) and unlike (P12) particles are as follows:
P11=n2 P22=(1-n)2 P12=2n(1-n) (14)

Three separate stability ratios, W”, W22, and Wu have to be calculated using equation
(13) to define W,. The probability that a given collision between two particles leads to
adhesion is [Hogg et al., 1966]:

1/W,= nz/Wn + (1—n)2/W22 + 2n(1-n)/ W12 (15)

1.4.2 Modeling HHF Theory

Wilson and Crimp [1993] base their model, Suspension Stability", on HHF theory
since it is the only model which incorporates the kinetic aspect of colloidal system
stability into quantitative expressions for the coagulation behavior of a system of
nonidentical particles, and is therefore adaptable to ceramic composites. HHF theory
was adapted to better predict the stability of ceramic composite suspensions by:

0 employing zeta potential, C, versus pH data to replace surface potential V4,, where

only particle size and density are necessary parameters for measurements rather than

21

details of ions groups present and their behavior with the medium, enabling
predictions for novel ceramic composites,

0 calculating an effective Hamaker constant after Shaw [1992, as cited in Wilson and
Crimp, 1993] from the Hamaker constants determined in a vacuum because particle
interactions in a medium are less than in a vacuum due to the presence of molecules
of the medium between the two interacting particles,

0 relying on a simplified Lifshitz method after Bleier [1983] to calculate Hamaker
constants since a method for the calculation was not addressed by HHF theory,

0 expanding the expression for the energy (VA) of interaction of the particles
themselves due to van der Waals forces to allow for other than H/a<<l , that is, small
particle separations,

o deriving a relationship between the relative volume fraction of particles of the two
particles and their radii to the overall proportion it used in the overall stability ratio

(WT) to permit input of the relative volume fraction of components.

The ranges of stability are indicated by pH where log W values are greater than 40
because at large separations of the particles, the errors resulting from the approximations
of the potential are small [Hogg et al., 1966]. Neither 10% variations in the Hamaker
constant, nor a :1: 5° C change in temperature from room temperature, affect the predictive

abilities of the program [Wilson and Crimp, 1993].

22

2 Experimental Procedure

The preparations and procedures used to investigate the colloidal behavior, green
and sintered densities, and resulting microstructure of SHS composite {TiBZ/A1203}, and
composites of SHS TiBz combined with each of Sumitomo AKP-50 and Alcoa
Superground A-1000 A1203 are described in this section. The starting composite
materials and all laboratory chemicals and polishing compounds were obtained from
commercial sources.

The equipment necessary for this investigation included scales accurate to 0.001
gram, a Matec Electrokinetic Sonic Amplitude (ESA) 8000, a Fisher Scientific pH meter,
a cold isostatic press, a CM Rapid Temperature 6” Furnace, a Hewlett Packard E23 78A
Multimeter, a Thermal Technology, Inc. resistance-heated, graphite furnace, an 1810
Amray scanning electron microscope (SEM) equipped with an Oxford Detector for
Energy Dispersive Spectroscopy (EDS), a JEOL JXA-84O SEM forbackscatter imaging,

and Nalgene" storage containers, graduated cylinders, and beakers.

2. 1 Starting Powders

2.1.1 Self-propagating-high-temperature-synthesis (SHS) TiB2
TiBz is covalently bonded in a hexagonal crystal structure typified by that of Ale

in which layers of titanium and boron atoms alternate in hexagonal coordination [Mroz,

1995]. To form TiBz, the SHS process combines readily available, high purity titanium

23

dioxide (T102), boron oxide (3203) and magnesium (Mg) powders according to the
following equation [Logan Ph.D. Thesis, 1992]:
TiOz + 3203 + 5Mg = TiB2 + 5Mg0 (16)

The composite TiBz/MgO product is then leached using a nitric acid solution to produce
sub-micron Ti32 particles [Logan Ph.D. Thesis, 1992]. The sub-micron particle size and
the particle-size distribution of SHS powders are appropriate for optimal green body
formation [Kingery, 1976, p. 9]. Advanced Engineered Materials (ABM), LLC
(Woodstock, GA), reports that Advanced TiBz Powder is a crystalline, non-pyrophoric,
homogeneous powder produced by a proprietary continuous process [AEM, LLC, 1995].

The physical properties reported by AEM, LLC for SHS TiBz are summarized in Table 1.

Table 1: Physical properties reported by the manufacturer for SHS powders, T182
and Composite {TileA1203}

 

 

 

 

 

 

 

 

Physical Properties SHS TiB2 SHS {TiB2/A1203}
Melting Point, °C/°F 3000/5430 2100/3812
Specific area (mT/g), 25 Not reported
minimum

Bulk density (g/cc) 0.94 1.3

Theoretical density 4.51 4.12

(hot PICSS) (g/OC)

Particle size range (m) 0.1 to 3 0.5 to 20

Median particle size (mm) 0.5 2

 

 

 

2.1.2 Alumina (A1203) Powders
a-A1203 is the important form of alumina in the fabrication of ceramics [Logan
Ph.D. Thesis, 1992; EMHSC, 1986; Jacobs and Kotomin, 1994]. The a-Aleg,

(corundum) structure can be viewed as hexagonal close packing of oxygen atoms with

aluminum atoms occupying two-thirds of the octahedral interstices. The unit cell (ten

24

 

atoms) contains two molecular units: each with three oxygen atoms (02) forming a

triangle having two aluminum atoms (A1”) on the z axis that lie symmetrically above and

below the oxygen-triangle [Jacobs and Kotomin, 1994].

2.1.2.1 Sumitomo AKP-50 AI203

Sumitomo Chemical America, Inc., High Purity Alumina, AKP-50 was selected
for its high surface area relative to particle size, which promotes Sintering in a-A1203
powders [Occhionero et al., 1988]. The chemical and impurity analyses and the physical
properties reported by Sumitomo Chemical America, Inc. for AKP-50 are summarized in
Table 2. Single crystals, abrasives, high strength alumina ceramics, and filler and
blending agents are applications of AKP-50 reported by the manufacturer [Sumitomo,

2001.]

Table 2: The chemical and impurity analysis and physical properties for AKP-50
A1203 reported by the manufacturer

 

 

 

 

 

 

Al203 99.995%T
Si <10 ppm
Na <10 ppm
Mg <10 ppm
Cu <10 ppm
Fe <10 ppm

 

Particle size (pm) 0.1 - 0.3
(Laser: Microtruck)
B.E.T. Special 9 - 15
surface area (mz/g)

 

 

 

 

 

2.1.2.2 Alcoa Superground A4 000 A120;

Alcoa Industrial Chemicals, Calcined Alumina, Realox Reactive Grade A-lOOO

was chosen for its origin and similarity in particle size to that used by Logan [1997]. The

25

chemical analysis by weight and the physical properties for Alcoa-SG reported by Alcoa
Industrial Chemicals are summarized in Table 3. The ceramic properties reported by the
Alcoa Industrial Chemicals for 10.5g pellets pressed in a one-inch diameter die at 34.5

MPa are summarized in Table 4.

Table 3: The chemical and impurity analysis and physical properties for Alcoa-SC
A1203 reported by the manufacturer

 

 

 

 

 

 

 

 

 

 

 

 

A1203 99.8 Wt %
NaZO 0.07
SiOz 0.02
F6203 0.02
CaO 0.02
8203 0.003
MgO 0.04
Median particle size 0.4
(pm) (Sedigmph

5100)

Percent through 100
44 um sieve -

Surface area (m‘/g) 8.8

 

 

Table 4: Ceramic properties for Alcoa-SG A1203 reported by the manufacturer

cc)
Densrty cc

6 )

0116 at

 

2.1.3 SHS Composite {TiBz/A1203}

To form composite TiB2/A1203, the SHS process combines readily available, high
purity titanium dioxide (TiOz), boron oxide (B203) and aluminum (A1) powders
according to the following equation [Logan Ph.D. Thesis, 1992]:

3T102 'l' 3B203 + lOAl = 3Tle + 5A1203 (17)

26

The composite TiBz/A1203 is ball milled to reduce the particle size of the as-reacted
powder and homogenize the distribution of TiB2 and A1203. Although it can be
formulated in any ratio, the nominal composition of the TileA1203 for armor tile
fabrication is 71 wt % A1203 and 29 wt % TiB2. Advanced Engineered Materials (ABM),
LLC, reports that Premier Composite TiBz/Alzog powder is a crystalline, non-pyrophoric,
homogeneous powder produced by a proprietary continuous process [ABM LLC, 1995].
The physical properties reported by ABM, LLC for SHS {TiBz/A1203} are summarized in

Table 1.

2.2 Electrokinetic Sonic Amplitude (ESA) Measurement

The ESA 8000 from Matec Applied Sciences (Northboro, MA) was used to
perform zeta (Q) potential measurements as a function of pH for each starting powder at a
volume fraction of 0.005 suspended in an indifferent, liquid electrolyte, potassium nitrate
(KNOg) at a concentration of 1x10” M . The Matec ESA 8000 is equipped with a probe
based electroacoustic sensor, as well as sensors for pH, conductivity, and temperature,
and a stirrer. The system is linked to a double-piston, digital titration unit for performing
automated potentiometric titrations and for generic volumetric additions with
simultaneous measurement of the electroacoustic signal for determination of the sample
zeta (2;) potential. The titrations were performed using 1 M nitric acid (HNO3) and 1 M

potassium hydroxide (KOH).

27

2.3 Stability Predictions

2.3.1 Hamaker Constant Calculation

The Hamaker constant in a vacuum was calculated [Bleier, 1983] for each starting
powder for entry into the computer program, Suspension Stability”. Dielectric constants
(permittivity, er) were fi'om the CRC Handbook of Chemistry & Physics, 79‘” Edition
[1998]; however, a dielectric constant was not available for TiB2. After checking
unsuccessfully with three manufacturers and other investigators for unpublished data, the
permittivity for Ti02 was used to approximate TiBz permittivity as both are divalent,
covalently bonded species that oxidize. The calculations of the Hamaker constant in a

vacuum are summarized in Table 5.

Table 5: The calculation of the Hamaker constant (Ar) in a vacuum [Bleier, 1983]
where M”) ~ 113.7((e,-1)’/[( e. +1)3”(e. +2)"’])

A:

Component

 

*The Hamaker constants for A1203 and TiB2 (1‘ i02) are averages since
permittivity (er) varies for each direction in the single crystal; the Hamaker
constant was computed for each permittivity provided and then averaged.

2.3.2 Computer Model

Material and system data including Hamaker constants in a vacuum, particle radii,
relative volume fraction of components, monatomic electrolyte concentration, and zeta

(C) potential versus pH measurements were entered into the computer program,

28

Suspension Stability©. The stability ratio versus pH data was transferred into ASCII

files and plotted using Microsoft Excel 97-SR2 software.

2.4 Slip Preparation and Casting

2.4.1 Electrolyte

J. T. Baker, Inc., Baker Analyzed Reagent, Potassium Nitrate (KNO3) (F.W.
101.11) was used to prepare the indifferent, liquid electrolyte in deionized water for

suspension preparation.

2.4.2 Slip Suspensions

Slip suspensions for casting were prepared at 50 wt % solids and at the pH chosen
for processing conditions predicted by Suspension Stability" for dispersion, coagulation
and heterocoagulation. Each suspension was stirred. The stirred suSpension was brought
to the processing pH by the drop-wise addition of 1 M HN03 or 1 M KOH as measured
by a pH meter (Fisher Scientific, fishersci.com). Composite TiB2/A1203 slips were
prepared from the SHS TiB2 and A1203 powders in the ratio 30/70 wt% similar to the
SHS composite {TileA1203}. The manufacturer reports SHS {TileA1203} as

nominally 29/71 Wtoflr T132 to A1203.

2.4.3 Ultrasonication

All suspensions were ultrasonicated (using the Branson Sonifier 250, Danbury,
CT, consisting of a power supply, a converter, and a hem). Sonication was performed to

eliminate any previous particle agglomeration. The ultrasonication time for zeta (Q)

29

potential measurements ranged between seven and twelve minutes; beyond twelve
minutes the temperature of the beaker was hot to the touch, introducing uncontrolled
temperature variation. Slip suspensions for casting were ultrasonicated for the optimum
time of 20 minutes to break agglomerates [Yeh, 1996], but the optimum time was divided
into two consecutive ten minute periods to replenish the ice bath used to keep the
suspension at a constant temperature. Sonicator output readings were maintained at 60
kHz through occasional adjustments. The frequency drifted during ultrasonication when

viscosity increased.

2.4.4 Plaster Mold Preparation

Plaster of Paris (100% Gypsum) was added to deionized water in the ratio 250g
plaster/ 165 ml water to form absorbing molds. A detailed description of mold
preparation can be found in Slimasting [1997], pp. 14-17. Twenty-five negative molds
were cast to ensure a minimum of five samples were available for each of the three
composite recipes: SHS composite {TiBz/A1203}, SHS TileAKP-SO A1203 and SHS
TileAlcoa Superground A-1000 A1203. The negative molds were formed five at a time
using a bar fitted with five machined lucite forms so that the impression in the plaster in
each weighing dish was approximately 6.2 cm (I) x 0.8 cm (w) x 0.6 cm (h) for a
minimum 3.0 cc sample. Afier drying in air for one week, each mold was sawed in two

and rubber banded back together for ease of sample release after slip casting.

2.4.5 Casting

Overfilling of each mold to allow for leakage and settling was required. The

weight of solids prepared for each batch was based on a mold height of 0.8 cm or 4.0 cc

30

per sample. The weight of material required for at least six samples of 4.0 cc volume for
TiB2/A1203 at 4.12 g/cc was 98 g. The 50 wt % slips were poured into molds in groups of
six (or seven given slip volume increased during processing) by pouring layer upon layer
of slip until each mold was filled. A non-reactive, stainless steel spatula was used as a
guide to pour the slip into the mold. The high viscosity of 50 wt% slip prevented pouring
fiom beakers directly. Pouring the slip into the molds could take as much as 1.25 hours.

Samples were air-dried four to seven days prior to unmolding.

2.5 Traditional Binder

Union Carbide Chemicals and Plastics Co., Inc., CARBOWAX (Polyethylene
Glycol (PEG)) Compound 20M, designated PEGZOM, flaked) was used as a binder for
each of the composite systems. Optimum green and sintered densities had been obtained
for A1203 at 2 wt% PEG20M [Walker et al., 1992]. The AKP-50 and Alcoa Superground
A-1000 composites were pressed into disk shaped, green bodies at 2 wt% PEGZOM
binder. A Carver press and three gram die were used to form the disks. The larger
surface area of the SHS Composite particles required 6 wt % PEG20M to form green
bodies.

Under a fume hood, PEG20M flake was placed in a. glass beaker on a hot plate;
ethanol was added and the mixture was stirred until the flakes dissolved. The composite
powders were added and ultrasonicated (Branson Sonifier 250, Danbury, CT) for five
minutes at 60 kHz output then returned to the hot plate and stirred with a non-reactive,

stainless steel spatula until the ethanol evaporated.

31

2.6 Cold Isostatic Pressing (CIPing)

All samples except for the SHS {TiB2/A1203} were double bagged in latex; each
was tied with soft string and placed in the cold isostatic press (ISO-Spectrum, Inc.) for two
minutes at a specified pressure before Sintering. Although the desired specified pressure
for all samples was higher, the specified pressure ranged from 105 to 300 MPa due to the
variability of the press operation. The SHS {TiBz/Alzog} samples were not pressed.
Even at low pressures <100 MPa, the SHS {TiBz/Ale3} particles penetrated the bags.
Whether latex, polyurethane or polyethylene, the bags leaked when pressing SHS

{TiBz/A1203}. Green densities were plotted as a function of pressure applied by the CIP.

2. 7 Green Bodies

2.7.1 Density Measurement

The samples were trimmed and sanded with 600-grit paper to near rectangular
shapes. A digital slide caliper was used to measure the length, width and height of each
sample and then the sample was placed on a balance to measure weight (Appendix C,

Tables 26-28).

2.7.2 Binder Burnout and Thermogravimetric Analysis (TGA)

For the PEG processed samples, gentle heating in crucibles in a furnace (CM
Rapid Temperature 6” Furnace, Bloomfield, NJ) according to one of two schedules
(Table 6) was accomplished to remove the PEG binder prior to density measurements or

pressureless Sintering.

32

Table 6: Binder burnout schedules for PEG processed samples

 

 

 

Schedule 1 Schedule 2
o Ramp up temperature from 100 to 450 o Ramp up temperature from 100 to 250
°C in six hours, °C in one hour,
hold for three hours, 0 hold for one hour,
ramp up temperature further from 450 a ramp down temperature from 250 to
to 550 °C in three hours, 100 °C in one hour
hold for one hour, and
then ramp down temperature from 550
to 100°C in three hours

 

 

Walker et al. [1992] suggested thermogravimetric analysis (TGA) of PEG processed
samples. TGA was performed at a heating rate of 10 °C/minute in air. SHS
{TileAle3} samples were heated through a range of 35 to 500 °C, and AKPSO and
Alcoa-SG samples were heated through a range of 35 to 350 °C to determine if all binder

was removed prior to density measurements and pressureless Sintering.

2.7.3 Conductivity Measurement

The Hewlett Packard B2378A Multimeter was used to test for conductivity in a

yes-no manner indicated by a beep for yes on all green bodies.

2.8 Pressureless Sintering

The samples were sintered in an Argon (Ar) atmosphere in a resistance-heated,
graphite furnace (Thermal Technology, Inc., Santa Rosa, CA). The samples were sintered
in a three-layer tower constructed of graphite crucibles with a sheet of Grafoil® flexible
graphite as a platform for each layer and graphite tape (grade GTA) sealing the tower.

Pressureless Sintering was accomplished according to one of two schedules (Table 7)

33

 

[Logan Ph.D. Thesis, 1992]. The samples were grouped: one of each processing

condition, four samples per layer, that is, 12 samples per sintering run.

Table 7: Pressureless sintering schedules for all samples

 

Schedule 1 Schedule 2

 

 

- Set fumace at 35 % power to 800 °C, 0 Set fumace at 35 % power to 800 °C,
0 continue heating at the rate of 25 °C per 0 continue heating at the rate of 25 °C per

 

minute to 1000 °C, then 10 ° C per minute to 1000 ° C, then 10°C per
minute to 1700 °C, and minute to 1800 °C, and
0 hold for four hours at 1700 °C 0 hold for four hours at 1800 °C

 

2.9 Sintered Samples

2.9.1 Density Measurement

Density measurements of sintered samples were performed using a balance placed
above a deep bowl (approximate capacity 3 liters) of deionized water supported by two
stationary slabs of TiB2. The dry weight of the sample was taken by placing the sample
on the top of the scale, and the weight of the sample submerged in the water was taken by
suspending a wire basket from under the scale. The method for computing the density
(pa (g/cc)) of the sintered sample follows the Archimedes method described in Jones and

Berard [1972]:

WD _ WDpL (16)

pa = Va — WD ‘Wss

where W0 is the dry weight of the sample in grams (g), V, is the apparent volume of the
sample in cc, p), is the density of the liquid in g/cc, and Wss is the weight of the saturated

sample when submerged in the liquid.

34

 

2.9.2 Conductivity Measurement

The Hewlett Packard E2378A Multimeter was used to test for conductivity in a

yes-no manner indicated by a beep for yes on all sintered samples.

2.9.3 Mounting and Polishing

Samples were placed in a bakelite form so the vertical cross section of the slip
cast specimen could be viewed and pressed at a pressure of about 27 MPa. The mounted
specimen was hand polished through a sequence of ever finer sand papers before
automatic polishing for microhardness measurements and scanning electron microscope
(SEM) viewing.

For each sample, the excess bakelite was ground off with a 180 um grade paper
(coarse red) on a belt sander and then hand polished with increasingly finer papers (Table

8).

Table 8: Hand polishing papers for sample preparation in the order used

 

 

 

 

 

 

Micron Grade Brand Name Manufacturer
50 um Tufbak Durite T421, 240-A Norton, USA
133
40 pm 413Q Wetodry Tri-M-ite 3M
Paper A, weight W2, 320
C042
30 um Tufbak Durite T421, 400-A Norton, USA
15 pm Wetodry Tri-M-ite Paper A, 3M
weight 600

 

 

 

Further grinding and polishing for microhardness measurements [Mullins, 1999] began
with two days of grinding for 15 minutes every hour with 15 um diamond paste in
kerosene on load plates followed by continuous polishing for 8 hours twice over two

days, with 0.05 pm silica.

35

 

For porous and pitted samples that could not be polished, cleaning for SEM
viewing was accomplished by sonicating (Cole-Farmer Instrument Company #8853

ultrasonicator, Vernon Hills, IL) for 10 to 15 minutes in an acetone bath.

2. 10 Scanning Electron Microscopy (SEM) Observations

2.10.1 Powders

A SEM mount was prepared for each of the starting powders by dusting two-sided
carbon tape affixed to the graphite mount. The powders were observed with an 1810
Amray SEM at 20.0 kV equipped with an Oxford Detector for Energy Dispersive

Spectroscopy (EDS).

2.10.2 Polished Specimens

The JEOL JXA-840 SEM was used in the backseatter mode at 20.0 kV to view

the microstructure of each polished specimen.

2. 1 1 Microhardness Measurement

The microhardness measurements were performed in accordance with the
American Society for Testing and Materials (ASTM) Designation: C 1327 — 96a,
Standard Test Method for Viekers Indentation Hardness of Advanced Ceramics. The 500

g rather than 1000 g load was used when the material crushed easily with the 1000 g load.

36

3 Results And Discussions

Ceramic composites were prepared for three different composite systems from the

four different starting powders: SHS TiBz/AKP-SO A1203, SHS TiB2/Alcoa SG A-1000
A1203, and SHS Composite {TiBz/Alzog}. The three different composites were formed
into samples by either mixing and pressing with a traditional binder (PEG20M), or slip
casting at the chosen processing pH (Table 11), and then pressureless sintered in an
Argon (Ar) atmosphere. The data collected from the investigations described in the
previous section include the calculated Hamaker constant (Table 5), temperature (°C),
density, volume fiaction, particle size, zeta potential (Q), stability ratio data (W), green
densities (g/cc), thermogravimetric analysis (TGA), sintered densities (g/cc),
microhardness measurements, and scanning electron micrographs. These data were used
to:

0 compare each colloidally-processed composite to that prepared with the traditional
binder PEG20M as to the effectiveness of Suspension Stability‘D in predicting
optimum suspension conditions for colloidal processing of TiB2/A1203 ceramic
composites, and

0 compare the microstructures of the colloidally-processed, pressureless-sintered
TiB2/A1203 ceramic composites with the dry-mixed, hot-pressed TiBz/A1203 ceramic
composites prepared by Logan [1997], which are associated with penetration

resistance in ceramic armor.

37

3. 1 Properties of Tim/Aha, Suspensions

3.1.1 Electrokinetic Sonic Amplitude (ESA) Measurement

Low concentration suspensions (0.5 vol.%) of each starting powder were prepared
and the Matec ESA 8000 measured the pressure amplitude per unit of applied electric
field (ESA (60)), temperature (°C), volume of acid and/or base added, and the pH during
each titration. It also computed the dynamic mobility (114(0)) and zeta potential (4), and
reported these as a function of the measured quantities. Suspensions were prepared for
each of the A1203 powders and the SHS TiB2 powder at three different electrolyte
concentrations (Figures 9, 10, and 11) to determine if, and at what electrolyte

concentration, optimal zeta potentials (4) were present for processing.

 

[— AKP-50 A1203 h 1x104 M 10103 ——AKP-50 A1203 1. 1310-3 M 10103 —-AKP-50 A1203 h 1310-2 M 10105]

 

200.0 ~—
150.0 ——

100.0 ——
50.0 —
0.0 + e i

-50.0 —~
-100.0 __
-150.0 ——
-200.0 -_

3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0

I

-—4

—t
/

m

i-

Zeta Potential (mV)

 

pH

Figure 9: Zeta potentials determined from ESA data collected using the Matec ESA
8000 for AKP-50 A1203 suspended in three different concentrations of electrolyte.

38

 

r—Alcea so A1203 1- 1:10-4 M 10103 --Alcoa so A1203 1. 1x103 M 10103 -—A|coa so A1203 1. 1:10.: M 1010?]

 

 

 

 

300.0 1
:’>‘
a 200.0 «—
3 100.0 __
E
*5 0.0 fi4
'3' 1000
a - . ~~
fl
-2000 ——

3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
pH

Figure 10: Zeta potentials determined from ESA data collected using the Matec
ESA 8000 for Alcoa SG A-1000 A1203 suspended in three different concentrations of
electrolyte.

 

[— sns 11112 b 1x104 M 10103 —s11s r1112 1- 1:10.3 M 10103 —sns 11112 b 1110-2 M 10103]

30.0 ——
20.0 -
10.0 —~

0.0 1 1 1 . e r .
-l0.0 .
-20.0 —
-30.0 —

3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0

T

I

l

Zeta Potential (mV)

 

I

pH

Figure 11: Zeta potentials determined from ESA data collected using the Matec
ESA 8000 for SHS TiB2 suspended in three different concentrations of electrolyte.

39

The electrolyte concentration of 11110'3 M KN03 was optimal for zeta potentials
(C) for each A1203 powder. The SHS {Tile A1203} powder was suspended in 1x10'3 M
KN03, and the zeta potential (mV) versus the pH was plotted for each powder using

Microsoft Excel 97 SR-Z (Figure 12).

 

 

—— Alcoa SG - - - -AKP-50 — SHS TiBZ —SHS Composite

 

 

 

 

 

 

 

 

150.0
% 100.0 «e
: 50.0 «e
.59.
E 0.0 1
a; -50.0 .-
13 -1000 --

-1500 -_

 

3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
pH

Figure 12: Zeta potentials for each starting powder suspended in 1x10'3 M
electrolyte from ESA data collected using the Matec ESA 8000.

The estimate for the minimum potential for stability is i 25 to 50 mV [Hunter,
1993, p. 422]. Therefore, the SHS TiB2 and SHS composite {TiB2/A1203} appeared to be
unstable at all pH; AKPSO was stable between about pH 4 and 6, and pH 8.5 and 10; and
Alcoa-SG was stable between about pH 4 and 5.5, and pH 9 and 10. Except for the SHS
composite {TiB2/A1203}, the Q—potential crossed the axis of zero potential for all the
starting powders between pH 7 and 8; the point of zero Q-potential was also the

isoelectric point (iep) [Heimenz 1997, p. 566].

40

There is no reported iep for TiB2 as determined by a search of the joint
Computerized Engineering Index and BI Engineering Meetings database (Bi
COMPENDEX). However, an iep for titania powders is reported as pH 7.5 when the
surface chemistry is affected by an inorganic such as A1203 and as low pH 6.1 when the
surface chemistry is affected by an organic material [Greenwood and Kendall, 1999].
The iep for SHS TiB2 at the optimum electrolyte concentration (1x10'3 M KN03) for
TiB2/A1203 composite processing was between pH 7.38 and 7.50.

The iep for A1203 five different a-Ale3 powders from the same manufacturer is
reported as pH 9 [Franks and Lange, 1999]. The iep for the AKP 50 A1203 (Figure 9) was
not in agreement with the reported iep at pH 9, but at lower electrolyte concentrations the
iep was consistent, ranging between pH 7.3 and 7.5. The iep for the Alcoa SG A1203
(Figure 10) was also not in agreement with the reported iep at pH 9, but at lower
electrolyte concentrations was not as consistent, ranging between 6.8 and 7.3 at the lower
electrolyte concentrations. The different (manufacturing/processing) origins of the oc-
A1203 powders as well as the different impurities present (Tables 2 and 3) produced
differences in surface chemistry that affected colloidal properties [Everett, 1988, p. 8;
Cerovic et al., 1995]. These differences in surface chemistry may then account for the
variations between the iep reported here and in the literature for the 01-A1203 powders.
The increased electrolyte concentration was expected to shrink the diffuse double layer
around the particle [Hunter, 1993, pp. 90-92] and increase the C-potential, but the iep was
expected to remain consistent for a pure material. Variations in the molecular activity of

the impurities and hence the surface chemistry may account for the inconsistency in

41

either the AKP 50 or the Alcoa SG A1203 iep at all electrolyte concentrations (Tables 2
and 3).

The iep is the point at which electrophoretic mobility is zero; therefore the
potential energy of repulsion between particles is minimal and the optimum condition for
coagulation of a particular powder is present [Heimenz 1997, p. 567]. Generally, if two
powders of different C-potentials are compared - all other factors being equal - the one
with the higher absolute value of the Q—potential is expected to be more stable with
respect to coagulation, and the one with the lower absolute value of the potential, less
stable [Heimenz 1997, p. 567]. However, if the suspension consists of a composite of
different particles — where all other factors are not equal — stability cannot be easily
generalized. Rather, DLVO and HHF theories applied to Q—potential measurements
provide a more precise estimate of stability of multiple, differing components in
suspension [Hogg, 1966; Wilson and Crimp, 1993]. By modeling DLVO and HHF
theories, the other unequal factors, including density, particle size, the interaction of
dissimilar electrical double layers, and coagulation kinetics, can be taken into account to
predict the stability of a composite suspension.

The Q-potential results for the SHS {TiB2/A1203} were not conclusive, and
possibly unstable at every pH. Therefore, three suspension processing conditions were
chosen to reflect the range of pH: pH 4 (acidic), pH 7 (neutral) and pH 9 (basic). Further
calculations using DLVO and HHF theories to predict stability of the SHS composite

powder were not possible because of the instability of the powder at every pH.

42

3.1.2 Stability Ratio (W)

For the composite systems SHS TiB2/AKP 50 A1203 and SHS TileAlcoa SG A-
1000 A1203, the Stability Ratio (W) was computed (Figures 13 and 14) to predict the
stability, and conversely the coagulation kinetics, of the composite suspensions. For each
powder, the calculated Hamaker constant in a vacuum (Table 5), temperature (°C),
volume fraction, concentration of the electrolyte (M), particle radii (,um), C—potential
(mV) vs. pH data, and the pH of the start and finishing points were entered into the
computer program Suspension Stability? The program bases calculation of the logro W
versus pH data on DLVO and HHF theories, and takes into account the factors of the
different components in suspension. The 10810 W versus pH data were plotted using

Microsofi Excel 97 SR-2 (Figures 13 and 14).

_._ SHS 'mrztsrrs 1:132 _.. sns TiBZ:AKP50 A1203 +AKP50 A1203tAKP50 A1203
350 a

 

2503
§2004
Si
@150.
O
1-1100.
50.

0 -

-so 1
pH

Figure 13: Stability ratio data prepared from the computer program, Suspension
swim", for SHS TiB; and AKP 50 A1203.

 

 

 

a.
U!
0‘
\I
as
\D

10

43

-.- SHS T182 : SHS T182 -.- SHS TlBZ:Alcoa-SG AI203 + Alcoa-SC AlZO3:AIcoa-SG A1203

350 -
300 - ‘

 

 

 

Figure 14: Stability ratio data prepared from the computer program, Suspension
Stabilityo, for SHS TiB2 and Alcoa-8G A-1000 A1203.

The program can predict ranges of stability by pH where log1o W > 40 [Wilson
and Crimp, 1993]. Tables 9 and 10 summarize the relative stability between components,
that is, where log10 W > 40 as predicted from the stability plots in Figures 13 and 14,

respectively.

Table 9. Relative stability between SHS TiB2 and AKP50 A1203 predicted by
Suspension Stabilioio

 

 

Stability SHS TiBz/ SHS TiB2] AKPSO A1203/
Ratio W SHS TiBz AKPSO A1203 AKPSO A1203
Interactions Interactions Interactions
Range of Predicted pH 4-6 pH 4-6 pH 4-7
Stability and and and
pH 8.5-9.5 pH 8.5-9.5 pH 8.0-9.5

 

 

 

 

 

 

44

Table 10: Relative stability between SHS TiB2 and Alcoa-8G A1203 predicted by

 

 

Suspension Stability°
Stability SHS TiB2/ SHS TiBz/ Alcoa-SG A1203/
Ratio W SHS T1132 Alcoa-SG Al203 Alcoa-SG A1203
Interactions Interactions Interactions
Range of Predicted pH 4-6 pH 4-6 pH 4-6.5
Stability and and and
pH 8.5-9.5 pH 8.5-9.5 pH 7.5-9.5

 

 

 

 

 

 

Suspension processing conditions were chosen to reflect three variations in

stability of the components: dismrsed - where both components were stable, particle

double-layers were large and like-charged, repulsive forces dominant, and thoroughly

mixed in suspension; coggglated - where both components were unstable, particle double-

layers were small and zero-charged, attractive forces dominant, and thoroughly

agglomerated in suspension; and heterocoagulated - where one component was stable and

 

the other unstable, particle double-layer sizes and charges were dissimilar, and partially

agglomerated in suspension. Heterocoagulation in the SHS TiB2 plus A1203 composites

occurred with the SHS TiB2 unstable with respect to the A1203. Table 11 summarizes the

processing conditions chosen for the three composite systems investigated.

Table 11: Summary of processing conditions chosen for the three composite systems

 

 

 

 

 

 

 

 

 

investigated
Processing Conditions SHS Composite SHS TiB2] SHS TiB2/
TiB2/A1203 AKPSO A1203 Alcoa-SG A1203
Traditional Binder W6 PEG PEG—'— ‘
Dispersed pH 4 pH 4 pH 4
Coagulated pH 7 pH 7.5 pH 7
Heterocoagulated pHT pH 8 pH T

 

 

45

3.2 Efiect of pH on Green Body Density

3.2.1 Material Loss and Sample Attrition

With all liquid evaporated during slip casting and drying, each batch of each
composite recipe prepared by a particular processing should yield approximately 98
grams of sample material. However, material loss was significant (Table 12). All of the
material was cast into samples, but the processing steps of removing the samples from
molds and cold isostatic pressing caused sample disintegration. Cold isostatic pressing
completely destroyed the first set of SHS composite samples. Another batch of the SHS
composite was slip cast and consequently not cold isostatically pressed prior to green

density measurements to preserve sample integrity.

Table 12: Material loss during green body forming for each composite recipe and
processing pH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Material Loss
Composite Recipe Processing pH during Green Body
Forming
SHS TiB2-AKP 50 A1203 4 74%
SHS TiB2-AKP 50 A1203 7.5 94%
SHS TiBz-AKP 50 A1203 8 98%
SHS TiB2-Alcoa SG A1203 4 65%
SHS TiB2-Alcoa SG A1203 7 84%
SHS TiB2-Alcoa SG A1203 8 82%
SHS CompositeTiBz-AIZO3 4 78%
SHS CompositeTiBz-Ale3 7 71%
SHS CompositeTiBz-Ale3 9 49%

 

 

46

The material loss was greatest in the SHS TiB2/AKP 50 A1203 system processed
at pH 8 with less than 2% of the starting material remaining. The SHS composite system
processed at pH 9 had the least material loss with over 50% of the starting material
remaining after processing. These findings may be consistent with A1203 being soluble
under basic conditions and TiB2 being soluble in a mixture of H202 and HNO3 [Wilson,
2001]. Wilson [2001] also reports that the SHS composite powder is not a mixture of the
two components as observed in the SEM image of the SHS composite powder (Figure
22) where the large (charging) particles were thought to be the non-conducting A1203 and
the smaller (non-charging) particles the conducting TiB2. Rather both components
constitute each particle creating a new type of surface chemistry. These composite
particles may account for the material loss in the SHS composite not following the same
trend as the other SHS TiB2 plus A1203 systems (Table 12).

In addition to the problem of material loss, the number and size of samples
available also varied by starting material and processing condition (Table 13). A greater
ntunber of smaller size samples were present after squeezing in the cold isostatic press

(CIP) due to the original samples breaking into smaller ones.

47

Table 13: Sample attrition during green body forming for each composite recipe
and processing pH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

' 1
Number of Number of AVfiLXZgh
. . . Samples Intact Samples ,
f
Composrte Rec1pe Processrng pH After Casting Available after C13.1.:rllable pt;
(100%= 7) ClP Measurements (g)
SHS TiBz-AKP 50 A1203 4 7 10 2.6
SHS TiBz-AKP 50 A1203 7.5 6 8 0.74
SHS TiB2-AKP 50 A1203 8 3 4 0.45
SHS TiB2-Alcoa SG A1203 4 6 9 3.84
SHS TiBz-Alcoa 86 A1203 8 6 11 1.59
SHS CompositeTiBz-Al203 4 5 7‘ 3.14
SHS CompositeTiB2-AI2O3 7 7 9‘ 3.15
SHS CompositeTiB2-Al203 9 7 9‘ 5.59
‘SHS Composite not ClP'd

For the SHS composite system, the samples processed at pH 9 experienced the
least attrition compared to the other processing conditions and the sample size averaged
5.59 g. For both of the other composite powders, the samples processed for dispersion
(pH 4) showed the least attrition and the “dispersed” sample size within each system
averaged more than twice the average size of the samples processed for heterocoagulation
and coagulation. The number and size of samples were significantly lower for the SHS
TiB2/AKP 50 system processed at pH 8.

Each composite system began with a total of 294 g (98 g of starting material for
each of three processing conditions). In the SHS TiB2/AKP 50 system, only about 11%
of the starting material remained after processing, and in the SHS TiB2/Alcoa-SG and

SHS composite systems, only about 23% and 34% remained, respectively. A large part

48

of the starting material was lost through overflow and adhesion to the molds during slip

casting as well as trimming of the samples for dimension and density measurements.

3.2.2 Green Body Density Measurements

Green densities were measured as a function of composite recipe and pH (Figure
15). Green density measurements generally ranged from 1.34 g/cc to 2.77 g/cc, or 32.5%
to 67.5% of the theoretical value (4.12 g/cc). The SHS composite system processed at
pH 9 had the narrowest range of variation in densities measured for any one particular
starting material or processing condition. The highest densities for both the SHS
TiB2/AKP 50 and SHS TiB2/Alcoa-SG green bodies were measured in those samples
processed for dispersion at pH 4 (Figure 15). Green body densities measured for SHS
composites processed at pH 4 were lowest. The lowest green body densities found for

any composite were for the SHS TiB2/AKP 50 processed at pH 7.5 and pH 8.0.

49

. AKPSO Comp [3 Alcoa-SG Comp A SHS COMPOSITE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.00 1 , 5: 5
2.90 - 1 ,2 _ _ 1 - -J
2.80..“—w J-+p1 11
270,. _d_n,_, _7- ,
2.60 -_ _ _ _ _ _ «._ 1.
A 2.50- 7_’fi_-_ 1__ _
g) 2.40 m J E? _
E 2.30 e». — [ l —— _1 —— i”, 2_
.,_. 2.20 .. LL. - -____,. ‘_ _
g 2.10 .ml. firm 2
Q 2.00 _ ._ t _ --p . 2-...
.g» 1.90 -._ __._ ..___
‘8 1.80 - 2. _- -1 2
a 1.70 - 2 d .ng ____,__
83 1.60 7,; _1-_- _ L
65 1.50 1 J 1,
1.40 _)*_,__$ ' .-_ e 1
1.30 '1' 3,. .-_, i
1.20 __,_4 1 2'__ 2 2 .
1.10 ' ._ 1 __- 1
1.00 . 1 1
6 , 7 8 9 10
Processrng pH

Figure 15: Green density vs. processing pH for each composite recipe

50

3.2.3 Green Density vs. Cold Isostatic Pressure

Neither a decrease in the range of variation in green density nor an improvement
in overall green densities was achieved with cold isostatic pressing (Figure 16). The lack
of any significant improvement combined with a significant risk of damage to samples

during cold isostatic pressing rendered this technique very disadvantageous in improving

 

 

 

 

 

 

 

 

green density.
3.00
D
250 ——eww _ “13* A - fl 2‘ 2 __ h 5
A A .
3 200 1- __ , ‘EE e-_ f ,_ i 2- 2
a fl T
E 150 3 ‘ '
'2 ° “ f‘“‘ ’ “*‘—“”' ' . 1 — —1
£1.00 ,. —*——— — _ _ _2 mashrfl ___ mm _
i
0 0.50 52,, ______2_._. ,
eSumitomo 1:1Alcoa ASHS
0.00 . , , , ,
0 50 100 150 200 250 300 350
Pressure (MPa)

Figure 16: Green density vs. pressure applied to composite samples during cold
isostatic pressing

3.2.4 Green Body Conductivity

All green bodies were non-conductive across the length, width, and height of each
sarnple. Placing the two electrodes on the any face of the sample also indicated non-

conductance.

51

3.3 Sintered Density

3.3.1 Binder Burnout and Thermogravimetric Analysis (TGA)

The binder burnout schedules were successful in removing the polyethylene
glycol (PEG) binder from all samples prepared without colloidal processing (Figures 17,
18, 19). Although calibration errors moved starting points from the 100% point, the
change in TGA curves showed that binder burnout before sintering removed 6 wt% PEG
from the SHS {TiB2/A1203}, and 2 wt% PEG, fi'om each of the SHS TiB2/AKP 50 and

SHS TiB2/Alcoa SG composite samples.

100.0

99.0 5____. -F __ _ __

 

 

 

 

98.5

Mass (%)

98.0 _, ,_

 

 

 

 

 

97.5 5-

 

 

 

 

97.0 , 1

0 50 100 150 200 250 300
Temperature (°C)

Figure 17: Thermogravimetric analysis (TGA) for the SHS TiB2 — AKP 50 A1203
composite green samples prepared with a traditional hinder; the 2 wt%
polyethylene glycol (PEG) binder was removed by binder burnout before sintering.

 

I

52

101.0

 

100.5 —

 

100.0

 

 

Mass (%)
t8
1

i3
o
1
l
l

 

 

1
1
1
1

 

 

 

98.0 ,

0 50 100 150 200 250 300
Temperature (°C)

 

Figure 18: Thermogravimetric analysis (TGA) for the SHS TiB2 - Alcoa SG A1203
composite green samples prepared with a traditional hinder; the 2 wt%
polyethylene glycol (PEG) binder was removed by binder burnout before sintering.

 

101.0
100.0 -___ \ —
A990 7‘— \X
9", 98.0 \ -— ~~———~———~-
8 97.0

a 96.0
1' 95.0

E 94.0 ———— \ ~—

93.0 "—"
92.0 I I 1 1 1

0 50 100 150 200 250 300
Temperature (° C)

 

 

 

 

 

 

 

 

 

 

 

Figure 19: Thermogravimetric analysis (TGA) for the SHS {TiB2/A1203} composite
green samples prepared with a traditional hinder; the 6 wt% polyethylene glycol
(PEG) binder was removed by binder burnout before sintering.

53

3.3.2 Material Loss and Sample Attrition

As was the case for the green samples, attrition was most severe in the SHS

TiB2/AKP 50 system processed at pH 8, and only one sample was available for sintering.

3.3.3 Sintered Density Measurements

Sintered densities were measured as a function of composite recipes and pH
(Figures 20(a) and 20(b)). Although the SHS composite green densities were among the
lowest at pH 4, the SHS composite sintered densities at pH 4 were among the highest.
The sintered densities of the SHS composite were greater than any other composite
system under any processing condition; in addition, unprocessed SHS (PEG binder)

yielded the greatest sintered density.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.00 - __ —_.77 i 5 . y. i _
A A A A
3.50 4e __. _..—_ ._-____.--. ____‘__ __A 5 .r 1
a B 9 1
3 00 E — . D i
'3‘ - e u V— — ——— 1
39 2 so 1
M
g 200 -_ A- 5- 5 z
r .... 5 1
3 1
.E
m 1.00 ~———-—-~-— ~~— —— _. #._ _2_ ____-_.d__- 1
0.50 -__.___
C AKP 50 Composite [:1 Alcoa SG Composite ASHS Composite I]
0.00
PEG pH 4 pH 7 pH 7.5 pH 8 pH 9
Processing Condition

Figure 20(a): Sintered density (g/cc) vs. processing condition for each composite
recipe

54

 

 

 

 

a 100.00
a
o
'5
g 90.00 ~e ”-4 A ~-—A——— ‘____5___._- -——% ————d
0
i D A
°\° 80.00 --e—Q—-—~——i~—————. ————— --~—~
v B E C]
Q ' a 1:1
2 70.00 -______, , — ——— , — —— —
o
n
'u
E 60.00 ,.-_ ------ _ _Z _
E ASHS DAlcoa SG OAKP 50
50.00

 

 

 

PEG pH4 pH7 pH7.5 pH8 pH9
Processing Condition

Figure 20(b): Sintered density (% Theoretical) vs. processing condition for each
composite recipe

3.3.4 Consistency of Sintered Microstructure with Suspension Stabilityc’ Predictions

Using the samples with PEG binder as a baseline for comparison, the
microstructures of the sintered samples in each of the three composite systems (Figure
21) were evaluated for consistency with the dispersion, coagulation, and
heterocoagulation behavior of the TiB2 and A1203 as predicted by Suspension Stability©.
The results are summarized in Table 14 and pictured in Figures 21 and 21(a-l). Predicted
and observed dispersion behaviors of TiB2 in A1203 for the two component systems were
in agreement. Acidic, neutral or basic processing conditions did not affect the hoped for
dispersion, coagulation nor heterocoagulation behavior of the SHS composite system.

The SHS powders were insensitive to colloidal processing.

55

In the two component systems, that is, SHS TileAKP 50 A1203 and SHS
TiB2/Alcoa SG A1203 composite systems, the microstructures differed between those
processed for dispersion, coagulation and heterocoagulation. The SEM micrographs
showed porosity was present in all three processing conditions to varying degrees. The
microstructure at pH 4 (Figure 216)) showed fine TiB2 phases uniformly distributed in an
A1203 matrix with very little porosity. In the coagulated microstructures (Figures 21(g)
and 21(k)), grains of A1203 and TiB2 are distinguishable with much porosity. In the
samples processed for heterocoagulation (Figures 21(h) and 21(1)), coarse TiB2 grains are
visible in the A1203 matrix, and the degree of porosity is much lower. The dispersed
processing condition resulted in the most uniform and finest distribution of TiB2 in A1203
with low porosity. Both SHS TiB2 plus A1203 two-component-systems were sensitive to
colloidal processing, and the microstructures reflected that Suspension Stability“a

effectively predicted the coagulation behavior of the SHS TiB2 plus A1203 two-

component-systems.

Table 14: Evaluation of sintered microstructure for consistency with processing
behaviors

Condition

 

56

 

SHS TiB Alcoa SG

.1" r .
.."J’. ’-.-1 t‘
.‘

    

SHS TiB7/AKP-50

 

SHS{TiBZ/AIZO

”I 31.". \o‘;

  

PEG

 

Dispersion

 

Coagulation

 

Heterocoagulation

 

 

 

 

 

 

Figure 21: Backseatter scanning electron micrographs (20.0 kV) of the
microstructures of each of the three composite systems at the four processing
conditions; markers are 100 11m in every micrograph; white areas are the TiB2, gray
areas are the A1203, and black areas are pores.

57

 

Figure 21(a): Backscatter scanning electron micrograph (20 kV) of SHS composite
{TileAlzog} processed with PEG20M binder; marker (white line at bottom of
micrograph) is 100 pm; white areas are the “82, gray areas are the Al203, and
black areas are pores.

     

w t ,

1 ..‘

Figure 21(b): Backseatter scanning electron micrograph (2 kV) of SHS composite
{TiBz/Al203} processed at pH 4; white areas are the 1182, gray areas are the Al203,
and black areas are pores.

58

 

Figure 21(c): Backseatter scanning electron micrograph (20 kV) of SHS composite
{TiBZ/Alzog} processed at pH 7; marker (white line at bottom of micrograph) is 100
pm; white areas are the TiBz, gray areas are the Al203, and black areas are pores.

 

Figure 21(d): Backscattcr scanning electron micrograph (20 kV) of SHS composite
{TiB2/Al203} processed at pH 9; marker (white line at bottom of micrograph) is 100
pm; white areas are the TiBz, gray areas are the A1103, and black areas are pores.

 

(pa .0}.

 

. 3‘ , ,_.‘ ,- a.
Figure 21(c): Backseatter scanning electron micrograph (20 kV) of SHS TileAKP
50 A1203 processed with PEG20M binder; white areas are the TiBz, gray areas are
the A1203, and black areas are pores.

 
    

Figure 21(i): Backscatter scanning electron micrograph (20 kV) of SHS TiBz/AKP
50 AIZOJ processed pH 4; white areas are the “82, gray areas are the Al203, and
black areas are pores.

60

 

. , ‘_ t; ,
1" «wt-9"». ”‘3" " l ’,

Figure 21(g): Backseatter scanning electron micrograph (20 kV) of SHS TiBz/AKP

50 AI203 processed pH 7.5; white areas are the TiB2, gray areas are the Al203, and
black areas are pores.

,______,__, n ”A--. ,__ .7.— -7-» .7 V-___:

Figure 21(b): Backscatter scanning electron micrograph (20 kV) of SHS TiBz/AKP
50 Al203 processed pH 8; white areas are the TiBz, gray areas are the AleJ, and
black areas are pores.

61

 

Figure 21(i): Backseatter scanning electron micrograph (20 kV) of SHS TiBz/Alcoa
SG A1203 processed with PEGZOM binder; marker (white line at bottom of
micrograph) is 100 pm; white areas are the TiB2, gray areas are the AIZOJ, and
black areas are pores.

 

Figure 210): Backseatter scanning electron micrograph (20 kV) of SHS TileAlcoa
SG Al203 processed at pH 4; marker (white line at bottom of micrograph) is 100
pm; white areas are the “82, gray areas are the A1203, and black areas are pores.

62

53%. it: '-
«VI “'th “-i A ‘

 

Figure 21(k): Backseatter scanning electron micrograph (20 kV) of SHS TileAlcoa
SG Al203 processed at pH 7; marker (white line at bottom of micrograph) is 100
pm; white areas are the “82, gray areas are the Al203, and black areas are pores.

 

Figure 21(I): Backseatter scanning electron micrograph (20 kV) of SHS TileAlcoa
SG Al203 processed at pH 8; marker (white line at bottom of micrograph) is 100
pm; white areas are the Tim, gray areas are the A1203, and black areas are pores.

63

 

Figure 22: Scanning Electron Microscope (SEM) image of SHS {TileAI203}
composite powder dusted onto carbon tape; the large charging particles were
thought to be the non-conducting Al203 and the small particles were thought to be
the conducting TiB2; recent investigations [Wilson, 2001] indicate most particles are
a mixture of both the TiBz and the AIZOJ.

3.3.5 Sintered Sample Conductivity

All sintered samples were conductive across their length, width, and height.

Placing the two electrodes on any face of all the samples also indicated conductance.

3.4 Microstructure

3.4.1 SHS Composites

Among the microstructures made from SHS composite starting powder, there
were no significant differences. In the SHS composite samples, the TiBz surrounded the
A1203 in an interconnecting network, which was visible from the SEM micrographs
(Figures 21 and 21(a—d)) and supported by the conductivity measurements. Thus, the
free-sintered SHS composite powders, no matter the processing conditions, produced the
microstructure most similar to the “continuous” microstructure (Figure 1) defined by

Logan [1997].

3.4.2 SHS Ti82 / A1203 Composites

In the other SHS TiB2 plus A1203 two-component-systems, the “continuous”
microstructure was not evident in the SEM micrographs (Figures 21 (e-j, 1), except in
some areas of the micrograph of the SHS TileAlcoa SG A1203 composite processed for
coagulation at pH 7 (Figure 21(k)). All the microstructures (Figures 21(e-j, 1)), but the
SHS TiB2/Alcoa 80 A1203 composite processed for coagulation at pH 7 (Figure 21(k)),

were similar to the “discontinuous” microstructure (Figure 2) defined by Logan [1997].

65

Although there were large agglomerations of TiBz (Figure 21(k)) in the SHS TiBz/ Alcoa
86 A1203 processed at pH 7, there were also distinct areas of the TiBz surrounding grains
of theA1203. The TiBz was interconnected even in the discontinuous microstructures
(Figures 21(e-j, 1)), as the measurements for conductivity were positive across all

dimensions of the sintered sample where there was no conductivity in the green bodies.

3.5 Microhardness Measurement

Even at a reduced load of 500 g rather than 1000 g for the indentation test, the

samples crushed easily, and the microhardness data was inconclusive.

66

4 Conclusions

The computer model Suspension Stability"D was effective in predicting optimum
suspension conditions for colloidal processing of two-component ceramic composites.
For SHS TiBz (30 wt%) plus A1203 (70 wt%) composite systems, the predicted pH value
of 4 was suitable for slip casting and reduced the extent of agglomeration such that the
SHS TiB2/AKP 50 A1203 and SHS TiBz/Alcoa SG A-IOOO A1203 composite systems
processed at these conditions achieved the highest green body densities. However, the
process of slip casting created samples highly vulnerable to physical damage and material
loss.

In both the SHS TiBz/AKP 50 A1203 and SHS TileAlcoa 86 A1203 composites
prepared in other than acidic conditions, material loss was high, which was consistent
with the solubility of A1203 under basic conditions. It was expected that composite
systems with the highest green body densities would yield sintered composites with the
highest densities. The data for both the SHS TiB2/AKP 50 A1203 and SHS TiB2/Alcoa
86 A1203 composite systems processed at pH 4 yielded sintered densities lower than
those processed at pH 7 and above. This trend was consistent with A1203 going into
solution under basic conditions [Wilson, 2001], thereby leaving material with a greater
percentage of the denser TiB2. Also, the result of fewer and/or significantly smaller (less
than half the average weight) samples in those processed at pH 7 was likely to create
more error in these measurements, which may also have accounted for this discrepancy in
the data where the highest green body densities did not produce the highest sintered

densities.

67

That the computer model Suspension Stability‘D was also effective in predicting
coagulating behavior of the SHS TiB2 plus A1203 composites was evident in the
backseatter micrographs of the colloidally-processed samples compared to the traditional
binder PEGZOM samples. The SHS TiB2 behavior was sensitive to colloidal processing
and dispersed, coagulated or heterocoagualated with respect to both the AKP 50 and
Alcoa SG A-lOOO A1203.

Suspension Stability" was not effective in predicting optimum suspension
conditions for colloidal processing of SHS composite {TiB2/A1203}. Green body
densities of the SHS composite {TiBz/Al203} were slightly higher for those processed at
pH 7, but sintered densities were similar (within 0.5%) no matter the processing
condition. The sintered densities of the traditional binder samples, which were not
colloidally-processed, were less variable and slightly higher than those colloidally-
processed. Although processing at pH 4 caused some material loss in the SHS composite
{TileAle3} system and slightly lower green body densities as would be expected if
TiBz was removed after going into solution, the green body densities, the sintered
densities, and the invariant microstructures in the sintered samples, indicated the SHS
composite {TiB2/A1203} system was insensitive to colloidal processing.

When the microstructures of the traditional binder PEGZOM and colloidally-
processed, pressureless-sintered SHS TiB2 plus A1203 composite systems were compared
to the SHS (or non-SHS-but-dry-mixed), hot-pressed TiB2/A1203 ceramic composites,
only the SHS TileAlcoa 86 A1203 processed at pH 7 was of further interest for ceramic
armor applications. The coagulated behavior of the SHS TiB2/Alcoa SG A1203 processed

at pH 7 was able to produce some of the “continuous” microstructure associated with

68

ballistic penetration resistance with a final density comparable to the high densities
achieved with the SHS composite {TiB2 /A1203} starting powders. With more control
over coagulation behavior, the desired microstructure could dominate the SHS
TiBz/Alcoa SG A1203 ceramic composite system.

When the microstructures of the traditional binder PEGZOM and colloidally-
processed, pressureless-sintered SHS composite {TiBZ/A1203} composite system were
compared to the SHS (or non-SHS-but-dry-mixed), hot-pressed TiBz/A1203 ceramic
composites, all were consistent with the “continuous” microstructure associated with
ballistic penetration resistance. The SHS composite {TiB2/A1203} starting powders
continue to be of interest for armor applications as the factors necessary for the
“continuous” microstructure appeared to be inherent in the poWder itself and not

dependent on any colloidal processing of the starting powders.

69

5 Future Work

In this research effort, the colloidal processing of TiBZ/A1203 was explored.
Further research is recommended to better understand the following:

- electrolyte options to reduce the apparent solution and loss of the TiB2 and A1203
[Wilson, 2001] and to increase opportunities for adjusting the pH during
processing so as to oppositely charge the components and agglomerate the TiB2
around the A1203 particles as suggested by Hogg et a]. [1966] and Franks et a1.
[1995]

o advantages of freeze drying then pressing to form samples rather than slip casting
of colloidal suspensions, which experienced high material loss and sample
attrition

o differences in zeta potential and stability between carbothermic Ti82 and SHS
TiB2; Logan [1997] used carbothermic TiBz for some of the penetration resistant

ceramic armor targets

70

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71

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Ceramics," J.Am.Ceram.Soc., 79 [10] 2687-95 (1996)

W.D. Kingery, H.K. Bowen, and DR. Uhlmann, Introduction to Ceramics, Second
Edition; John Wiley & Sons: New York, 1976, p. 9

74

F.F. Lange, “Powder Processing Science and Technology for Increased Reliability,” .1.
Am. Ceram. Soc., 72 [1] 3-15 (1989)

F.F. Lange, B.V. Velamakanni, J.C. Chang and D.S. Pearson, “Colloidal Powder
Processing for Structural Reliability: Role of Interparticle Potential on Particle
Consolidation,” Structural Ceramics Processing, Microstructure and Properties Proc. of
the Riso International symposium on Metallurgy and Mater. Sci, Riso Natl Lab, Riso
Library, Roskilde, Den. 1990, p. 57-78.

J. Liu and PD. Ownby, “Enhanced Mechanical Properties of Alumina by Dispersed
Titanium Diboride Particulate Inclusions,” J. Am. Ceram. Soc., 74 [1] 241-243 (1991)

K.V. Logan, "Elastic-Plastic Behavior of Hot Pressed Composite Titanium
Diboride/Alumina Powders Produced Using Self-Propagating High Temperature
Synthesis," Georgia Institute of Technology, Ph.D. Thesis, September 1992

Commmrication from K.V. Logan, Ph.D., Principal Investigator, School of Material
Science and Engineering, Georgia Institute of Technology to T. Furrnaniak, Project
Engineer, Contract No. DAAEO 7-95-C-R040, US. Army Tank Automotive Research
Development and Engineering Center (TARDEC), February 28, 1997

London (1930) as cited in D. J. Shaw, Introduction to Colloid and Surface Chemistry,
Fourth Edition; Butterworth-Heinemann: Oxford, 1992, p. 215

Matec Applied Sciences. The ESA-9800. [Online] Available http://www.matec.com
lesa9800.htm, January 20, 2001

A.G. Merzhanov, “Self-Propagating High-Temperature Synthesis: Twenty Years of
Search and Findings,” Keynote Address, The Institute of Structural Macrokinetics, USSR
Academy of Sciences, Chemogolovka, Moscow, USSR, Combustion and Plasma
synthesis of High-T emperature Materials, Z.A. Munir and J .B. Holt Editors, VCH, New
York, 1990, pp. 1-3

C. Mroz, "Titanium Diboride," Am. Ceram. Soc. Bulletin, 76 [6] 158-9 (1995)
Communication from J. Mullins, Laboratory Technician, Weapons Material Research
Directorate, Army Research Laboratory, Aberdeen Proving Ground, Maryland, August
1999

O’Brien (1986, 1990) as cited in BA. Wilson and MJ. Crimp, "Prediction of Composite

Colloidal Suspension Stability Based upon the Hogg, Healy, and Fuerstenau
Interpretation," Langmuir 1993, 9, 2836-2843

75

M.A. Occhionero, S.L. Marallo, A.E. Karas and BE. Novich, “Influence of Surface Area
and Particle Size Distribution on Sintering and Microstructure Development,” Symposium
on Sintering of Advanced Ceramics, American Ceramic Society, Cincinnati, OH, 2-5
May 1988

RM. Ogorkiewicz, “Development of Lightweight Armour Systems,” Keynote Lecture,
Lightweight Armour Systems Symposium, Royal Military College of Science,
Shrivenham, Swindon, UK 28-30 June 1995

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 174

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 178

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 190

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 216

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 217

D. J. Shaw, Introduction to Colloid and Surface Chemistry, Fourth Edition; Butterworth-
Heinemann: Oxford, 1992, p. 218

Shaw (1992) as cited in B.A. Wilson and M.J. Crimp, "Prediction of Composite Colloidal
Suspension Stability Based upon the Hogg, Healy, and F uerstenau Interpretation,"
Langmuir 1993, 9, 2836-2843

Smoluchowski (1916, 1917) as cited in R. Hogg, T.W. Healy and D.W. Fuerstenau,
“Mutual Coagulation of Colloidal Dispersions,” Trans. Faraday Soc. 1966, 62, 1638-
1651

Stern (1924) as cited in D. J. Shaw, Introduction to Colloid and Surface Chemistry,
Fourth Edition; Butterworth-Heinemann: Oxford, 1992, p. 182, and P.C. Heimenz and
R. Rajagopaian, Principles of Colloid and Surface Chemistry, Third Edition Revised and
Expanded; Marcel Dekker, Inc.: New York, 1997, p.527

E. Strassburger, H. Senf, H. Rothenhausler, “Comparison of Failure Behaviour During
Impact and Ballistic Performance of Different A1203 Ceramics,” Lightweight Armour
Systems symposium, Royal Military College of Science, Shrivenham, Swindon, UK 28-
30 June 1995

76

Sumitomo Chemical. Alumina products. [Online] Available http://sumitomo-
chem.co.jp/kiso_e/alumina/index.html, March 9, 2001.

M. Takeo, Disperse Systems; Wiley-VCH: New York, 1999, p. 1

M. Takeo, Disperse Systems; Wiley-VCH: New York, 1999, p. 5

J. Texter, Particle Characterization; Strider Research Corporation: Rochester, NY, 2000
W.J. Walker, Jr., J .8. Reed and SK. Verma, “Polyethylene Glycol Binders for Advanced
Ceramics,” Paper 52-EP-92, 94th Annual Meeting of the Am. Ceram. Soc., Minneapolis,
MN, April 12-16, 1992

S. Warden, Slip Casting; A&C Black: London, 1997, pp. 14-17

B.A. Wilson and M.J. Crimp, "Prediction of Composite Colloidal Suspension Stability

Based upon the Hogg, Healy, and Fuerstenau Interpretation," Langmuir 1993, 9, 2836-
2843

Communication from O.C. Wilson, Jr., “Characterization of Aluminum Oxide/Titanium
Diboride Composite Powders Formed by SHS Reactions,” Paper SI-013-01, 25th Annual
International Conference on Advanced Ceramics & Composites, American Ceramic
Society, Cocoa Beach, FL, 21-26 January 2001

P. Woolsey, D. Kokidko and S. Mariano, “An alternative Test Methodology for Ballistic
Performance Ranking of Armor Ceramic,” MT L TR 89-43, US. Army Materials
Technology Laboratory, Watertown, MA, 1989

Z. Yeh, “Colloidal Processing of SiC(w)/Si3N4 Ceramic Composites by Slip Casting.”
Michigan State University, Masters Thesis, February 1996

77

APPENDICES

78

APPENDIX A

Equations for Evaluating Armor Efficiencies

79

Tests of depths of penetration GDOP) are conducted to characterize the ballistic
performance of a specific armor material. DOP test data can be used to calculate the
mass efficiency (em), as well as space efficiency (e,) and the armor quality factor (qz),
which is a quality of particular interest to armor designers. The armor quality factor (qz)
relates both mass and space efficiencies and provides a quantity to compare between
different armor materials. The weight and space claim of an armor material is necessary
for armor designers to evaluate ballistic performance for protection of military ground
vehicles.

The following equations [Woolsey et al., 1989] were used to calculate space

efficiency (es) mass efficiency (em), and the armor quality factor (qz):

 

e,=——P"’”"'PR (17)
TCER
em=(PWrIN-PR)*pWITN zesaggfl (l8)
TCER * pCER pCER
q2 =e~ *es (19)

Pmm is the depth of penetration of the projectile into the semi-infinite witness plate
without the ceramic facing, PR is the penetration of the projectile into the semi-infinite
witness plate with the ceramic mounted to the front face, T can is the thickness of the
ceramic applied to the face of the witness plate, and p is the density of the respective
material. Each of these quantities is dimensionless.

The e," compares the areal density (AD), that is, (density "' thickness) of a material
to the areal density of the witness plate also called the backing material, which is usually
RHA steel. Aluminum is usually employed for DOP tests when the projectile velocity or

mass is too low to penetrate the reference material. When aluminum is used as the

80

witness plate, e". is then called the ballistic efficiency (11). The e,,. and e, of the witness
plate, that is, the reference material, is by definition equal to 1.0; results greater than 1.0

indicate better ballistic performance as compared to the reference material.

81

APPENDIX B

Electrokinetic Sonic Amplitude (ESA) Measurements

82

Table 15: Potentiometric Titration (POTN729.esa), 0.5 vol. °/o “32, 1x10'4 M KNO;

ESA

DynMob

m*2N‘e)

 

Net(meql1) (mPa’MN) (
W 0409

-0.330
-0.235
-0.130
0.000
0.010
0.080
-0.030
0.000
-0.010
0.180
0.320
0.454
0.594
0.749
0.914
1.083

0.394
0.380
0.389
0.383
0.357
0.358
0.352
0.358
0.349
0.358
0.382
0.359
0.358
0.385
0.388
0.370
0.374
0.379
0.382
0.380
0.388
0.383
0.382
0.383
0.378
0.378
0.372

1.

1.505
1.452
1.409
1.389
1.388
1.389
1.344
1.388
1.335
1.383
1.384
1.374
1.372
1.397
1.400
1.418
1.431
1.453
1.483
1.455
1.487
1.489
1.483
1.489
1.452
1.443
1.429
1.401
1.389
1.387
1.357
1.328
1.318
1.293
1.287
1.237
1.191
1.182
1.142
1.085
1.023

0.817

Phase
201: (mV) (doc)
17.563 -10.900
18.981 -8.700
16.450 -1 .300
16.271 -0.600
16.002 0.300
16.050 2.400
15.678 3.800
15.955 4.600
15.566 4.600
15.976 7.600
16.233 11.100
16.126 15.200
16.109 16.500
16.409 22.500
16.447 25.600
16.666 26.000
16.623 31.300
17.069 32.600
17.216 35.200
17.122 37.300
17.515 39.100
17.306 40.100
17.244 41.500
17.316 41.900
17.124 43.500
17.026 43.400
16.666 44.500
16.545 45.700
18.404 45.600
18.151 48.400
16.043 46.600
15.663 47.700
15.590 47.500
15.296 46.600
14.993 50.100
14.646 50.700
14.116 51.300
14.006 52.300
13.537 52.500
12.673 54.200
12.150 58.000
11.773 57.700
10.601 62.500
9.720 66.700
6.636 76.000
7.964 65.900
-7.146 101.400
-6.500 114.000
-6.266 132.200
-5.977 142.300
-6.093 153.300
-5.766 162.100
-5.761 173.500
-5.634 -175.100
-5.564 -159.600
-6.424 -149.400
-7.656 -141.700
-8.385 -1 37.900
-9.629 436.900
-10.306 -135.400
-11.529 -137.600
-12.661 -140.900

pH (unite)
3.900
4.020
4.150
4.160
4.190
4.230
4.270
4.260
4.290
4.320
4.420
4.510
4.600
4.690
4.790
4.660
4.970
5.060
5.150
5.240
5.330
5.430
5.540
5.640
5.750
5.660

9.910

83

Good.
(US/cm)

1885.000
1845.000
1820.000
1875.000
1877.000
1878.000
1804.000
1599.000
1597.000
1880.000
1877.000
1880.000
1883.000
1883.000
1888.000
1691.000
1897.000
1898.000
1707.000
1715.000
1718.000
1729.000
1740.000
1750.000
1758.000
1758.000
1783.000
1788.000
1773.000
1779.000
1788.000
1787.000
1789.000
1792.000
1800.000
1801.000
1808.000
1818.000
1822.000
1834.000
1847.000
1880.000
1882.000
1902.000
1925.000
1955.000
1992.000
2022.000
2088.000
2111.000
2170.000
2230.000
2288.000
2345.000
2413.000
2474.000
2534.000
2598.000
2883.000
2710.000
2775.000
2835.000

Temp
(600 C)

35.700
35.700
35.800
35.800
35.800
35.800
35.800
35.800
35.800
35.800
35.800
35.800
35.500
35.500
35.500
35.500
35.500
35.500
35.400
35.500
35.400
35.400
35.400
35.400
35.400
35.300
35.300
35.300
35.300
35.300
35.300
35.300
35.300
35.200
35.200
35.200
35.200
35.200
35.200
35.100
35.100
35.100
35.100
35.000
35.100
35.100
35.000
35.000
35.000
35.000
35.000
35.000
35.000

Acid (ml) Base (ml) Total (mt)

200 068
200.047
200.028
200 172
200.174
200.184
200 006
200 000
200.002
200.208
200.238
200.283
200 291
200 322
200 355
200 389
200.428
200 487
200 512
200 560
200 812
200 888
200 723
200.773
200 821
200 865
200 904
200 938
200 989
200.999
201 030
201 061
201 092
201.124
201 .157
201.192
201.222
201.281
201 307
201.384
201.425
201.489
201 561
201.838
201.726
201.819
201.925
202 037
202.185
202 300
202.454
202.817
202.788
202 980
203.153
203 344
203.533
203.720
203 905
204.078
204 245
204 393

Table 16: Potentiometric Titration (POTN733.esa), 0.5 vol. % TiB2, 11:10’3 M KNO3

 

Net (meq/1) (mPe‘MN) (m‘2N‘e) Zete(mV)
—30‘3'30 0.351 1

-0.235
-0.130

ESA Dyn Mob
0.328 1.254
0.301 1.149
0.303 1.157
0.300 1.149
0.301 1.150
0.278 1.058
0.278 1.081
0.280 1.089
0.292 1.118
0.287 1.099
0.282 1.077
0.279 1.088
0.274 1.048
0.284 1.085
0.277 1.059
0.278 1.083
0.277 1.081
0.270 1.038
0.289 1.032
0.288 1.028
0.257 0.985
0.258 0.982
0.250 0.958
0.237 0.910
0.234 0.898
0.223 0.854
0.219 0.840
0.209 0.801
0.200 0.789
0.197 0.755
0.185 0.711
0.181 0.894
0.173 0.888
0.181 0.819
0.159 0.810
0.152 0.583
0.144 0.553
0.138 0.523
0.119 0.457
0.112 0.429
-0.099 -0.380
0.0” -0.329
-0.078 -0.300
-0.072 -0.278
-0.073 -0.280
-0.092 -0.353
-0.112 -0.434
-0.148 -0.584
-0.192 -0.742
-0.243 -0.941
-0.284 -1.097
-O.328 91.283
-0.352 -1 .388
-0.388 -1.429
-0.383 -1.411
-0.387 -1.502
—0.407 -1.583
-0.437 -1.700
-0.487 -1.818
-0.503 -1.980
-0.544 -2.123

15.871
14.357
14.478
14.378
14.385
13.184
13.283
13.345
13.980
13.758
13.484
13.374
13.117
13.598
13.278
13.338
13.290
12.982
12.930
12.883
12.359
12.317
12.017
11.420
11.253
10.739
10.554
10.081
9.882
9.483
8.928
8.721
8.377
7.779
7.871
7.330
8.985
8.578
5.748
5.400
4.787
-4.145
-3.778
-3.479
—3.529
-4.451
-5.471
-7.108
-9.348
-11.852
-13.823
-1 5.912
-17.214
-1 8.005
-17.785
-18.943
-19.988
-21.448
-22.983
-24.741
-28.828

Phase
(doc)

-0.100
3.400
7.200
8.800

110.500

127.800

145.800

188.200

179.500
-189.800
482.100
-158.800
-154.100
-149.800
-148.900
-143.200
-140.500
-138.800
-138.200
-134.500
434.000
-133.400
434.300

pH (units)

4.000
4.130
4.180
4.170
4.210
4.250
4.280
4.270
4.310

84

Good.
(US/cm)

1712.000
1893.000
1724.000
1728.000
1723.000
1871.000
1872.000
1688.000
1731.000
1723.000
1728.000
1722.000
1734.000
1733.000
1742.000
1741.000
1749.000
1759.000
1758.000
1788.000
1780.000
1788.000
1798.000
1802.000
1813.000
1815.000
1823.000
1832.000
1830.000
1838.000
1835.000
1841.000
1844.000
1851.000
1859.000
1858.000
1N8.000
1878.000
1890.000
1895.000
1902.000
1923.000
1937.000
1983.000
1988.000
2020.000
2048.000
2087.000
2124.000
2189.000
2222.000
2280.000
2341.000
2398.000
2455.000
2512.000
2578.000
2838.000
2887.000
2738.000
2787.000

Temp
(den 0)

33.000
33.000
33.000
32.900
33. 000
33. 000
33.000
33. 000
32.900
32.900
32. 900
32. 900
32. 900
32.900
32 . 900
32.800
32.900
32. 900
32.900
32.900
32.900
32.900
32. 800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.700
32.700
32.700
32.700
32.700
32.700
32.700
32.700
32.700
32.700
32.700
32.800
32.700
32.700
32.700
32.700
32.800
32.800
32.800
32.800
32.800
32.800
32.800
32.500
32.800
32.500

Acid (ml) Base (ml)

0.047
0.028
0.088
0.088
0.068
0.008
0.000

3.473

4.154

Total (ml)
. O
200 047
200.026
200.132
200.134
200.144
200.006
200 000
200.002
200.171
200.198
200.226
200.254
200.283
200 317
200.354
200 392
200.435
200.481
200.530
200.586
200.846
200 707
200.766
200.820
200.869
200.912
200.949
200 981
201 009
201.036
201.062
201.090
201.118
201.147
201.171
201.202
201.242
201.285
201.337
201.395
201.452
201.512
201.580
201.859
201.746
201.844
201.947
202 064
202.195
202.333
202.481
202.646
202.817
202.987
203.166
203.354
203 539
203.721
203.891
204.055
204.220

Table 17: Potentiometric Titration (POTN731.esa), 0.5 vol. % TiBz, 1x10'2 M KN O 3

Net (meql1) (mPa'MN)
W

-0.280
0.000
0.020
0.120
-0.180
0.435
0.849
-0.045
0.000
-0.015
1.218
1.517
1.792
2.081
2.305
2.545
2.784
3.023
3.287

18.573
19.499
20.414
21.295
22.121
22.888

ESA

0.441
0.413
0.403
0.397
0.391
0.377
0.385
0.359
0.341
0.339
0.335
0.348
0.338
0.331
0.325
0.321
0.322
0.321
0.320
0.322
0.320
0.328
0.320
0.317
0.315
0.311
0.302

0.288
0.283
0.274
0.287
0.254
0.248
0.245
0.237
0.223
0.218
0.207
0.198
0.187
0.172

DynMob

1.579
1.541
1.518
1.497
1.439
1.474
1.372
1.304
1.295
1.281
1.328
1.293
1.287
1.244
1.231
1.238
1.231
1.226
1.238
1.228
1.252
1.229
1.218
1.211
1.198
1.181
1.128
1.107
1.087
1.055
1.029
0.979
0.953
0.943
0.913
0.858
0.841
0.798
0.782
0.720
0.884
0.807
0.554
0.497
-0.443
-0.429
-0.444
-0.494
-0.599
—0.899
-0.819
-0.985
-1.132
-1.198
-1.297
-1.354
-1.422
-1.483
-1.530
-1.811
-1.729
-1.880
-1.988

(m‘2N‘s) Zen (mV)
1

18.318
17.920
17.888
17.438
18.899
17.188
15.991
15.125
15.004
14.843
15.488
15.079
14.780
14.521
14.378
14.439
14.375
14.328
14.450
14.388
14.849
14.391
14.243
14.185
14.017
13.812
13.227
12.998
12.783
12.384
12.087
11.508
11.214
11.102
10.732
10.093
9.897
9.378
8.989
8.488
7.821
7.185
8.537
5.885
-5.228
-5.070
-5.242
-5.835
-7.078
-8.287
-9.882
~11.418
-1 3.405
-14.191
-15.388
-18.047
-18.851
-17.588
-18.183
-19.127
-20.538
-22.329
-23.599

Phase
(600)
-18.000
-16.300
-15.100
-14.100
-14.100
-11.900
-7.600
-9.000
-8.100
-6.600
-2.100
3.400
7.900
14.500
16.300
23.300
27.400
31.300
34.500
37.700
40.900
43.400
45.600
46.900
49.300
51.600
51.900
53.400
54.600
56.100
56.000
57.400
58.500
60.200
60.700
61.400
82.200
65.100
65.300
67.600
89.600
73.500
77.500
82.200
94.600
110.200
134.100
149.300
164.300
174.900
474.900
-166.000
458.700
-152.000
447.300
-143.600
-140.300
-136.400
-136.300
-138.000
-138.600
-136.800
-137.800

pH (units)

3.910
3.930
3.950
3.980
4.030
4.050
4.180
4.170
4.200
4.210
4.290
4.390
4.490
4.800
4.700
4.800
4.900
5.000
5.090
5.190
5.290

85

Cond.
(US/cm)

3358.000
3371 .000
3384.000
3358.000
3332.000
3353.000
3352. 000
3313.000
3303.000
3308.000
3353.000
3348.000
3350.000
3342.000
3348.000
3349.000
3353.000
3357.000
3385.000
3357.000
3388.000
3370.000
3378.000
3388.000
3398.000
3400.000
3403.000
3412.000
3415.000
3419.000
3418.000
3429.000
3428.000
3431 .000
3440.000
3445.000
3445.000
3458.000

Temp
(dos C)

38.000
35.900
35.800
35.900
38.000
35.900
35.800
38.000
38.100
38.000
35.800
35.800
35.800
35.800
35.800
35.700
35.800
35.700
35.700
35.700
35.700
35.700
35.800
35.800
35.800
35.800
35.600
35.800
35.500
35.500
35.500
35.500
35.400
35.400
35.500
35.500
35.400
35.400
35.400
35.400
35.400
35.400
35.400
35.400
35.300
35.300
35.300
35.300
35.300
35.300
35.200
35.200
35.200
35.200
35.200
35.200
35.200
35.100
35.100
35.100
35.100
35. 100
35. 100

Acid (ml)

0.052
0.073
0.073
0.073
0.032
0.073
0.073
0.009
0.000
0.003
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073
0.073

Base (ml)

0.000
0.073
0.077
0.097
0.000
0.180
0.243

Total (m1)

, 3—
200.052
200 146
200.150
200.170
200.032
200 233
200 316
200.009
200 008
200.003
200.390
200.450
200.505
200.559
200.606
200.858
200.704
200.752
200.801
200 853
200 905
200 961
201 017
201.073
201 126
201.179
201.215
201.252
201 290
201.327
201.383
201 397
201 429
201 480
201.490
201 521
201.553
201 587
201 828
201.875
201.731
201.790
201.851
201.917
201 992
202.072
202.167
202.263
202.382
202.508
202.643
202.796
202.958
203.129
203.312
203.506
203.698
203.899
204.088
204 275
204 455
204 824
204.777

Table 18: Potentiometric Titration (POTN717.esa), 0.5 vol. % AKP-S0 A1203, 1x104

M KNO;

 

14610116071) (mPa'MN) (m‘2IV'6)
W 1.79!

0.030
0.130
0.195
0.240
0.270
0.295
0.325
0.350
0.375
0.405

ESA 0111 Mob
6.148
1.837 6.324
1.854 8.401
1.696 6.596
1.926 6.726
1.966 6.917
1.996 9.044
2.011 9.114
2.005 9.066
2.032 9.210
2.015 9.130
2.007 9.096
1.962 8.963
1.941 6.796
1.920 6.701
1.762 6.076
1.633 7.404
1.430 6.482
1.272 5.768
1.089 4.935
0.993 4.502
0.982 4.450
0.957 4.337
0.910 4.126
0.905 4.102
0.823 3.731
0.766 3.474
0.666 3.110
0.626 2.636
0.551 2.499
0.488 2.213
0.431 1.952
0.368 1.669
0.310 1.407
0.251 1.138
0.201 0.912
0.153 0.693
0.071 0.324
-0.034 0.154
-0.065 -0.385
-0.141 -0.638
-0.199 -0.903
-0.287 -1 .302
-0.383 -1.646
-0.449 -2.035
-0.549 -2.492
-0.619 -2.810
-0.722 .3274
-0.624 .3740
-0.909 4.125
-1.026 4.664
-1 .129 -5.120
-1.242 -5.634
4.327 -6.021
-1469 -8.820
-1.583 -7.094
-1.701 -7.722
-1.829 -6.304
-1.966 4.926
-2.078 -9.438
-2.178 -9.894
-2.290 40.405
-2.388 40.650
-2.500 -1 1.383

Phase
201- (mV) (doc)
94. - .
96.660 -13.500
97.803 -13.300
99.927 -12.200
101.491 40.900
103.599 -10.500
105.106 -10.600
106.012 -10.100
105.738 -9.200
107.121 -6.500
106.228 -7.500
106.040 -6.500
104.647 -6.200
102.463 -5.200
101.457 -4.200
94.093 -3.100
66.266 -1.600
75.539 -1.700
67.197 -1.000
57.549 -0.100
52.492 -0.100
51.905 0.400
50.590 0.200
46.152 0.900
47.663 0.000
43.571 1.700
40.560 0.900
36.326 0.600
33.150 0.600
29.197 0.500
25.654 -0.100
22.621 0.000
16.519 -0.200
16.450 -0.900
13.336 -2.500
10.675 -4.700
6.114 -6.300
3.767 -21.600
-1.600 -94.000
4.505 447.600
4.469 -160.000
-10.571 -162.700
-15.252 -167.500
49.293 -168.600
-23.851 -169.600
-29.204 -169.700
-32.930 -171.300
-36.369 -171.700
43.664 -173.200
46.397 -173.300
-54.721 -174.100
-80.062 -174.200
-66.120 -174.300
-70.702 475.200
-77.767 -175.500
-63.256 -175.300
-90.721 -175.500
-97.532 -176.100
404.902 -175.600
-110.677 -175.600
-116.288 -175.800
422.290 -175.600
427.573 -175.500
-133.601 -175.600

[311 (units)

3.810
3.980
4.090
4.220
4.320
4.410
4.510
4.810
4.890
4.780
4.870
4.950
5.040
5.110
5.200
5.300
5.410
5.520
5.840

86

Good.
(US/cm)

121.000
123.000
125.000
127.000
129.000
130.000
132.000
133.000
138.000
138.000
140.000
143.000
148.000
149.000
154.000
158.000
183.000
187.000
170.000
172.000
173.000
173.000
174.000
175.000
176.000
177.000
178.000
179.000
180.000
181.000
183.000
184.000
185.000
187.000
187.000
189.000
191.000
193.000
195.000
197.000
198.000
201.000
204.000
207.000
211.000
215.000
219.000
228.000
232.000
241.000

Temp
(doc C)

31.300
31.300
31.300
31.300
31.300
31.300
31.300
31.300
31.300
31.300
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.200
31.100
31.100
31.100
31.100
31.100
31.100
31.100
31.100
31.100
31.100
31.100
31.000
31.000
31.000
31.000
31.000
31.000
31.000
31.000
31.000
30.900
31.000
31.000
30.900
30.900
30.900

Acid (ml)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000

Base (ml)
0.008
0.028
0.039
0.048
0.054
0.059
0.065
0.070
0.075
0.081
0.087
0.093
0.100
0.107
0.117
0.127
0.136
0.144
0.151
0.158
0.159
0.161
0.183
0.185
0.188
0.171
0.174
0.177
0.180
0.183
0.188
0.189
0.192
0.195

Total (ml)

200.006
200 028
200.039
200.048
200 054
200.059
200.085
200 070
200 075
200 081
200.087
200 093
200.100
200.107
200.117
200 127
200.136
200.144
200 151
200.156
200 159
200.181
200.163
200.185
200.188
200.171
200.174
200.177
200.180
200.183
200.186
200.189
200.192
200.195
200.198
200.201
200.205
200.209
200 213
200.217
200.221
200.228
200.231
200.237
200.243
200 249
200.256
200.284
200.273
200.284
200.295
200 308
200.322
200 339
200.359
200.383
200.412
200.446
200.479
200.516
200.581
200.812
200 872

Table 19: Potentiometric Titration (POTN719.6sa), 0.5 vol. % AKP-50 Ale3,1x10'3

M KNO;

Not(moql1) (mPa'MN) (m‘2/V‘9) 2616(mV)

1.973
2.133
2.302
2.502
2.748
3.020
3.329

ESA Oyn Mob
2.298 10.400
2.338 10.592
2.382 10.795
2.400 10.875
2.410 10.918
2.415 10.944
2.435 11.033
2.415 10.945
2.431 11.015
2.408 10.914
2.398 10.869
2.355 10.872
2.298 10.407
2.280 10.245
2.182 9.798
2.042 9.258
1.882 8.439
1 .888 7.851
1.524 8.910
1.348 8.101
1.270 5.758
1.208 5.488
1.139 5.185
1.051 4.787
0.972 4.407
0.873 3.957
0.822 3.729
0.778 3.527
0.731 3.318
0.693 3.142
0.847 2.932
0.584 2.555
0.482 2.184
0.402 1.823
0.319 1.448
0.245 1.112
0.118 0.527
0.032 0.144

-0.102 -0.480
-0.185 -0.838
-0.288 4 208
-0.377 4 .707
-0.485 -2.201
-0.578 -2.823
-0.882 -3.000
-0.757 -3.432
-0.858 -3.880
-0.980 4.358
4 .071 4.858
4.183 -5.385
4 .305 -5.920
4 .402 -8.358
4 .530 -8.943
4 .848 -7.479
4 .781 -7.989
4.880 -8.534
-2.038 -9.250
-2.145 -9.739
-2.284 40.280
-2.377 4 0.793
4.48 41.337
-2.832 41.981
-2.781 42.842

117.911
120.188
122.754
123.422
123.948
124.275
125.300
124.308
125.158
124.075
123.545
121.311
118.348
118.438
111.483
105.349
98.077
87.124
78.724
89.453
85.554
82.313
58.874
54.333
50.233
45.142
42.543
40.280
37.835
35.859
33.488
29.204
24.955
20.823
18.532
12.710
8.025
1.845
-5.288
-9.588
43.825
49.541
-25.195
-30.032
-34.370
-39.313
44.488
49.933
-55.880
-81.500
-87.890
-72.985
-79.824
45.829
-91.877
-98.024
408.280
411.828
418.118
424.033
430.301
437.498
445.404

Phase

(609)

5.400
5.900
8.200
8.500
8.400
7.000
7.500
8.000
8.200
8.500
8.800
9.800
9.800
10.300
10.800
11.200
11.700
12.500
12.400
12.800
13.000
13.500
14.100
13.900
14.000
14.200
14.200
14.000
13.400
14.400
13.700
13.400
13.200
12.500
11.500
9.100
2.400
-88.100
441.000
452.800
455.100
457.900
4 58.400
459.800
4 59.900
480.900
480.800
481.500
482.100
482.100
482.800
483.000
483.300
483.100
483.200
483.800
483.400
483.400
483.400
483.200
483.500
483.400
483.600

pH (units)

3.790
3.980
4.110
4.230
4.310
4.390
4.490
4.800
4.850
4.750
4.840
4.930
5.030
5.100
5.190
5.280
5.390
5.490
5.800
5.710
5.820
5.920
8.010
8.100
8.190

87

0000.
(uS/cm)

289.000
272.000
274.000
278.000
277.000
278.000
281 .000
283.000
284.000
287.000
288.000
292.000
293.000
298.000
299.000
302.000
305.000
308.000
31 1.000
314.000
315.000
318.000
317.000
319.000
319.000
321 .000
322.000
321 .000
323.000
323.000
323.000
325.000
327.000
327.000
328.000
329.000
332.000
334.000

851.000

Temp
(609 C)

32.400
32.400
32.300
32.300
32.300
32.300
32.300
32.300
32 .300
32.300
32.300
32.300
32.300
32.300
32.200
32.200
32.200
32.200
32.200
32.200
32.200
32.100
32.200
32.200
32.200
32.100
32.100
32.100
32.100
32.100
32.100
32.000
32.000
32.100
32.000
32.000
32.000

Add (ml)

0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000

8666 (ml) Total (m!)

0.007
0.027
0.038
0.045
0.050
0.055
0.081
0.088
0.070

0.289

0.550

0.687

200 007
200 027
200 038
200.045
200.050
200 055
200.061
200.066
200.070
200.076
200.082
200.088
200.094
200.100
200.107
200.114
200 122
200.129
200.135
200.140
200.144
200.147
200.150
200.153
200.158
200.159
200.161
200.163
200.165
200.167
200 169
200.172
200 175
200.178
200.161
200 184
200 188
200.192
200.196
200 200
200 204
200.209
200 214
200 219
200.224
200.230
200.237
200.245
200.254
200.264
200.276
200.289
200.305
200.322
200.342
200.368
200.395
200.427
200.461
200.501
200.550
200.605
200.867

Table 20: Potentiometric Titration (POTN723.esa), 0.5 vol. '/o AKP-50 Ale3,lx10'2
M KN03

       

N61 ESA Dyn Mob Zeta Phase Cond. Temp 8666 Total
(men/1) (mPa'NW) (WW8) (mV) (dog) 9“ (um) (Us/cm) (609 G) Add (01') (MD (MD

1 11 ;' '3; :e' -1 12 0'1'1 ' 019 " ’ 3
0.725 3.210 14.546 154.428 37.700 3.690 1092.000 35.100 0.019 0.019 200.036
0.750 3.211 14.549 154.509 37.700 3.910 1093.000 35.100 0.019 0.024 200.043
0.775 3.153 14.288 151.321 37.300 3.920 1077.000 35.200 0.005 0.000 200 005
0.805 3.155 14.293 151.395 37.200 3.970 1074.000 35.200 0.000 0.000 200.000
0.834 3.187 14.444 153.484 37.400 4.040 1091.000 35.100 0.019 0.049 200.088
0.684 3.190 14.458 153.779 37.500 4.140 1092.000 35.000 0.019 0.087 200.088
0.894 3.247 14.719 156.409 37.200 4.240 1095.000 35.100 0.019 0.064 200.103
0.919 3.282 14.768 157.285 37.400 4.380 1097.000 35.000 0.019 0.100 200.119
0.939 3.287 14.811 157.509 37.900 4.510 1101.000 35.000 0.019 0.113 200.132
0.959 3.238 14.860 156.258 38.800 4.820 1103.000 35.000 0.019 0.121 200.140
0.979 3.216 14.589 155.242 39.000 4.740 1107.000 35.000 0.019 0.126 200.147
0.994 3.195 14.484 154.228 38.000 4.830 1108.000 35.000 0.019 0.133 200.152
1.009 3.171 14.378 153.214 38.000 4.910 1109.000 34.900 0.019 0.138 200.157
1.024 3.143 14.252 151.957 39.600 5.010 1111.000 34.900 0.019 0.144 200.183
1.039 3.181 14.330 152.619 39.300 5.100 1113.000 34.900 0.019 0.149 200.166
1.054 3.088 13.902 146.336 39.600 5.190 1115.000 34.900 0.019 0.154 200.173
1.084 3.078 13.956 146.672 40.200 5.280 1116.000 34.900 0.019 0.159 200.176
1.074 2.981 13.425 143.292 40.200 5.360 1116.000 34.900 0.019 0.184 200.163
1.064 2.925 13.284 141.862 39.300 5.450 1123.000 34.900 0.019 0.169 200.168
1.094 2.820 12.786 138.558 41.100 5.530 1124.000 34.900 0.019 0.174 200.193
1.109 2.755 12.492 133.495 41.600 5.620 1130.000 34.600 0.019 0.180 200.199
1.129 2.600 11.792 126.057 42.000 5.720 1127.000 34.600 0.019 0.186 200.205
1.149 2.422 10.985 117.418 42.000 5.610 1134.000 34.600 0.019 0.192 200.211
1.189 2.310 10.474 111.966 42.900 5.920 1135.000 34.800 0.019 0.198 200.217
1.189 2.136 9.867 103.597 42.300 6.020 1137.000 34.800 0.019 0.203 200.222
1.204 2.008 9.106 97.451 42.800 8.120 1139.000 34.600 0.019 0.207 200.228
1.224 1.643 8.357 89.429 43.300 8.220 1144.000 34.600 0.019 0.211 200.230
1.244 1.688 7.857 81.968 43.700 6.320 1143.000 34.600 0.019 0.215 200.234
1.284 1.609 7.298 78.104 43.600 8.420 1143.000 34.600 0.019 0.218 200.237
1.284 1.493 8.771 72.526 43.300 8.510 1145.000 34.700 0.019 0.221 200.240
1.309 1.380 8.259 87.061 43.600 6.800 1147.000 34.700 0.019 0.224 200.243
1.334 1.261 5.612 82.330 43.300 8.700 1148.000 34.700 0.019 0.227 200.248
1.384 1.188 5.298 58.625 44.000 8.600 1148.000 34.700 0.019 0.230 200.249
1.394 1.108 5.027 53.947 42.900 8.690 1148.000 34.700 0.019 0.232 200.251
1.429 1.048 4.743 50.911 43.100 8.970 1148.000 34.700 0.019 0.234 200.253
1.489 1.003 4.551 48.686 43.400 7.040 1149.000 34.800 0.019 0.238 200.255
1.514 0.947 4.298 46.130 43.200 7.110 1150.000 34.800 0.019 0.238 200.257
1.583 0.638 3.799 40.618 43.100 7.200 1151.000 34.800 0.019 0.241 200.280
1.823 0.860 3.065 33.154 40.600 7.310 1152.000 34.800 0.019 0.245 200.264
1.863 0.545 2.472 26.570 39.300 7.430 1153.000 34.800 0.019 0.249 200.286
1.766 0.423 1.920 20.653 35.600 7.550 1158.000 34.800 0.019 0.253 200.272
1.656 0.297 1.347 14.485 30.800 7.880 1159.000 34.800 0.019 0.257 200.278
1.988 0.236 1.076 11.595 28.600 7.780 1159.000 34.800 0.019 0.280 200.279
2.102 0.130 0.586 8.327 8.000 7.660 1183.000 34.800 0.019 0.284 200.263
2.257 0.092 0.417 4.490 48.400 7.980 1185.000 34.500 0.019 0.286 200.267
2.441 -0.134 -0.608 -6.527 -90.400 8.090 1168.000 34.500 0.019 0.272 200.291
2.858 -0.216 -0.966 40.637 406.700 6.160 1187.000 34.500 0.019 0.278 200.295

-0.328 -1 .480 -1 5.935 -1 16.000 6.290 1178.000 34.500 0.019 0.261 200.300

-O.425 -1 .929 -20.797 -1 19.500 6.390 1174.000 34.500 0.019 0.268 200.305

-0.554 -2.512 -27.060 422.400 8.500 1161.000 34.500 0.019 0.292 200.311

-0.885 -3.016 -32.542 424.200 6.800 1162.000 34.500 0.019 0.298 200.317

-0.776 -3.526 -36.056 -1 25.700 6.710 1192.000 34.500 0.019 0.305 200.324

-0.902 4.094 44.199 426.800 6.820 1198.000 34.400 0.019 0.313 200.332

-1.016 4.820 49.689 427.800 6.930 1203.000 34.400 0.019 0.322 200.341

4.137 -5.161 -55.748 426.500 9.040 1214.000 34.400 0.019 0.332 200.351

4.282 -5.727 81.648 430.600 9.150 1225.000 34.400 0.019 0.344 200.383

4.384 -8.192 48.924 430.400 9.240 1238.000 34.400 0.019 0.358 200.375

4.502 -6.820 -73.754 -131 .000 9.380 1258.000 34.400 0.019 0.373 200.392

4.823 -7.368 -79.777 432.000 9.480 1273.000 34.300 0.019 0.391 200.410

4.747 -7.933 -85.603 432.100 9.580 1299.000 34.300 0.019 0.413 200.432

4.902 -8.838 -93.407 432.800 9.870 1329.000 34.300 0.019 0.440 200.459

«2.033 -9.233 599.926 433.400 9.770 1386.000 34.300 0.019 0.471 200.490

-2.187 -9.935 407.558 433.100 9.660 1415.000 34.300 0.019 0.506 200.527

-2.306 40.488 -1 13.537 433.900 9.960 1487.000 34.300 0.019 0.551 200.570

88

Table 21: Potentiometric Titration (POTN710.esa), 0.5 vol. % Alcoa SG A4000

M203, 15104 M KNO,

 

ESA Dyn Mob
Not (meg/1) (mPa'M/V) (m‘2N‘6)

-0.030 1.655 6.

0.000 1.859 8.624
0.025 1.673 6.693
0.000 1.657 6.814
0.120 1.666 8.782
0.190 1.905 8.842
0.240 1.900 6.616
0.260 1.666 6.783
0.315 1.679 6.722
0.355 1.651 6.590
0.395 1.616 8.439
0.440 1.786 6.196
0.465 1.719 7.962
0.545 1.620 7.521
0.610 1.534 7.120
0.665 1.366 6.447
0.760 1.225 5.668
0.835 1.050 4.876
0.905 0.669 4.035
0.964 0.716 3.325
1.009 0.620 2.661
1.039 0.578 2.676
1.064 0.539 2.506
1.069 0.466 2.267
1.114 0.427 1.966
1.139 0.366 1.709
1.164 0.309 1.434
1.169 0.250 1.160
1.214 0.205 0.951
1.239 0.159 0.739
1.264 0.122 0.567
1.269 0.096 0.456
1.314 0.096 0.445
1.339 -0.103 -0.476
1.359 -0.116 -0.537
1.379 -0.137 -0.636
1.404 -0.158 -0.733
1.439 -0.206 -0.957
1.474 -0.246 4.144
1.509 -0.262 4.312
1.544 -0.321 4 .494
1.579 -0.351 4 .631
1.614 -0.366 4 .793
1.653 -0.422 4 .961
1.693 -0.455 -2.116
1.736 -0.500 -2.326
1.766 -0.543 -2.524
1.636 -0.573 -2.664
1.903 -0.625 -2.905
1.973 -0.676 -3.142
2.046 -0.731 4.399
2.126 -0.763 .3640
2.222 -0.635 -3.863
2.327 -0.897 4.171
2.442 -0.966 4.491
2.576 4 .031 4.796
2.726 4 .069 -5.086
2.905 4.176 .5473
3.105 4.250 -5.620
3.329 4.346 -8.267
3.563 4.428 -6.646
3.672 4 .461 8697

Phase
201- (mV) («9)
107.998 -9.900
106.657 -9.600
107.723 40.400
109.777 -9.300
110.765 -6.300
110.457 -7.300
109.796 -7.000
109.310 -6.500
107.701 -5.700
105.622 -5.200
102.612 -5.300
100.096 4.200
94.326 -5.100
69.331 -5.600
60.666 -5.400
71.376 -5.600
61.201 -6.200
50.641 -6.900
41.745 -9.100
36.179 40.900
33.639 40.900
31.461 41.900
26.462 42.400
24.951 42.400
21.475 44.000
16.017 46.100
14.576 49.600
11.954 -24.100
9.292 -33.600
7.132 45.600
5.735 -63.600
5.599 49.500
-6.016 413.600
-6.753 425.000
-6.009 430.900
.9226 440.500
42.041 446.100
44.399 455.000
46.524 456.200
46.613 456.600
-20.543 460.600
-22.569 461.900
-24.700 462.900
-26.663 463.600
-29.307 463.500
-31.613 464.700
43.567 465.600
—36.621 466.500
49.619 466.600
42.672 467.900
45.935 467.400
46.965 469.000
-52.632 469.400
-56.665 469.500
40.543 469.700
-63.941 470.000
49.092 470.100
-73.463 470.000
-79.155 470.900
43.963 469.900
-67.131 470.100

pH (units)

3.890
3.920
3.930

9.170
9.280
9.380
9.490

9.720

9.830
9.930

89

Good.
(US/cm)

217.000
216.000
211.000
219.000
222.000
224.000
228.000
228.000
231.000
234.000
237.000
240.000
248.000
251.000
257.000
283.000
289.000
275.000
280.000
283.000
288.000
288.000
289.000
291.000
293.000
295.000
298.000
297.000
299.000
301.000
302.000
305.000
308.000
308.000
309.000
310.000
313.000
318.000
319.000
321.000
325.000
328.000
332.000
337.000
341.000
347.000
354.000
382.000
372.000
385.000
398.000
415.000
433.000
454.000
482.000
513.000
552.000
598.000
850.000
710.000
780.000

Temp
(699 C)

29. 700
29. 700
29.700
29.800
29.800
29.600
29.800
29.800
29.800
29.800
29.800
29.800
29.800
29.800
29.800
29. 500
29.800
29.800
29.500
29. 500
29. 500
29. 500
29. 500
29. 500
29.500
29. 500
29. 500
29.500
29. 500
29. 500
29.500
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.400
29.300
29. 300
29.300
29.300
29.300
29. 300
29. 300
29. 300
29.300
29. 300
29. 300
29. 300
29. 300
29 . 300
29. 300
29. 300

Acid (ml) 8666 (ml) T016! (111!)

0.008
0.011

200 O1 2
200 017
200 000
200.036
200 050
200.080
200 068
200.075
200 083
200 091
200.100
200 109
200.121
200.134
200.149
200.184
200.179
200 193
200 205
200 214
200.220
200.225
200 230
200.235
200.240
200.245
200.250
200.255
200.280
200.265
200 270
200 275
200 280
200 284
200.288
200.293
200.300
200 307
200.314
200 321
200 328
200.335
200.343
200.351
200.380
200.370
200.380
200.393
200.407
200.422
200.438
200.457
200.478
200.501
200.528
200 558
200.594
200.834
200.879
200.730
200 788

Table 22: Potentiometric Titration (POTN713.esa), 0. 5 vol. % Alcoa SG A-1000

M203, 1110.31“ KN03

Not(m6ql1) (mPa' MN) (m‘2N’6)
—2'.'082 346

 

2.097
2.128
2.151
2.178
2.198

ESA Dyn Mob
2.10.

2 319 10.828
2.305 10.781
2.295 10.718
2.300 10.738
2.282 10.851
2.278 10.833
2.288 10.580
2.253 10.515
2.238 10.449
2.243 10.471
2.234 10.427
2.233 10.423
2.227 10.394
2.221 10.388
2.220 10.380
2.200 10.271
2.188 10.211
2.173 10.142
2.152 10.043
2.108 9.827
1.991 9.292
1.790 8.354
1.821 7.588
1.472 8.870
1.314 8.131
1.170 5.459
1.034 4.828
0.877 4.090
0.719 3.354
0.588 2.852
0.415 1. 935
0.290 1. 353
0.188 0.878
0.109 0.507
0.092 0 428
-0.115 -0. 537
-0.181 -0. 752
-0.224 -1 .044
-0.280 4.305
-0.333 -1 .552
-0.394 4.837
-0.447 -2.087
-0.491 -2.289
-0.551 -2.589
-0.812 -2.855
-0. 881 -3. 177
-0. 781 ~3. 549
-0.828 -3.851
-0.914 4.283
4.020 4.758
4 .098 -5.109
4.207 -5.827
4.333 4.212
4.443 -8.728
-1 .524 -7.102
4.575 -7.338
-1 .575 -7.337

Zeta (mV)

135.552
134.739
134.058
134.244
133.290
133.028
132.319
131.543
130.881
130.905
130.359
130.304
129.987
129.584
129.435
128.373
127.821
128.718
125.470
122.713
118.057
104.334
94.491
85.753
78.520
88.125
80.220
51.031
41.850
33.078
24.140
18.875
10.922
8.321
5.341

th

(M)

17.800
17.800
17.200
17.500
17.900
17.400
17.800
17.800
17.800
17.700
17.700
17.700
17.800
18.100
17.400
17.800
17.800
17.900
18.200
17.900
18.300
19.000
18.100
18.300
17.700
18.200
17.500
18.800
15.800
14.000
11.000
8.100
-3.100
-30.800
-88.700
408.400
423.900
434.400
438.000
442.200
443.700
445.500
447.300
447.700
448.900
450.200
451.000
452. 000
-1 53. 700
453.400
454.800
-1 55. 000
458.000
455. 400
455. 700
458. 000
-1 55. 700

pH (units)

3.900
4.000
4.100
4.210
4.310
4.410
4.520
4.810
4.890
4.740
4.810
4.890
4.970
5.080
5.220
5.390
5.590
5.830
8.090
8.380
8.580
8.750
8.870
8.950
7.030
7.110
7.180
7.270

9.240

9.590
9.710
9.840
9.950
10.000
10.010

90

Good.
(US/cm)

872.000
885.000
859.000
858.000
852.000
848.000
845.000
841 .000
842.000
841 .000
840.000
839.000
837.000
837.000
838.000
835.000
833.000

Temp
(deg C)

29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.700
29.800
29.700
29.700

Acid (ml)

0.409
0.403
0.398
0.393
0.389
0.385
0.381
0.378
0.378
0.375
0.374
0.373
0.372
0.371
0.370
0.389
0.388
0.387
0.385
0.380
0.351
0. 338
0.325
0.318
0.308
0.302
0.297
0.292
0.287
0.282
0.278
0.270

0.258
0. 253
0. 248
0. 243

0.233
0.228

0. 218
0.213
0.207

0.192
0.183
0.174
0.183
0.150
0.135
0.118
0.093
0.083
0.029
0.009
0.005

8966 (ml)

0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.626
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828
0.828

Total (ml)

201 237
201.231
201.226
201.221
201 217
201.213
201.209
201.206
201.204
201.203
201.202
201 201
201 200
201.199
201.198
201.197
201.196
201.195
201.193
201.188
201.179
201.166
201.153
201.144
201.136
201.130
201.125
201.120
201.115
201.110
201.104
201.098
201.092
201.086
201.081
201.076
201.071
201.066
201.081
201.058
201.051
201.046
201.041
201.035
201.028
201.020
201.011
201.002
200.991
200.978
200.963
200.944
200.921
200.891
200 857
200.837
200.833

Table 23: Potentiometric Titration (POTN725.esa), 0.5 vol. % Alcoa SG A4000

 

 

M203, 1x10 2 M KN03
ESA Dyn Mob Phase

“(moo/1) (mPa'M/V) (m‘2N'6) Zota(mV) (dog) pH (units)
41.145 4.925 22951—259394 0.200 3.
-0.090 4.962 23.119 261.164 0.500 3.960
0.000 4.941 22.932 259.436 1.400 4.060
0.015 4.959 23.017 260.554 1.300 4.070
0.090 5.026 23.337 264.175 1.400 4.140
-0.015 5.033 23.354 263.697 0.900 4.140
0.000 5.042 23.394 264.033 1.000 4.160
0.200 5.027 23.333 264.251 2.100 4.220
0.325 5.043 23.411 265.256 3.200 4.330
0.440 5.120 23.772 269.466 3.500 4.450
0.535 5.144 23.666 270.713 4.300 4.590
0.600 5.231 24.293 275.330 5.500 4.740
0.640 5.242 24.343 275.933 6.900 4.650
0.675 5.276 24.514 276.062 7.600 4.960
0.705 5.266 24.560 276.645 6.300 5.060
0.729 5.267 24.556 276.597 6.600 5.130
0.759 5.340 24.603 261.441 9.900 5.220
0.769 5.290 24.573 276.956 10.900 5.310
0.624 5.294 24.592 279.421 11.600 5.400
0.659 5.276 24.506 276.242 12.900 5.490
0.694 5.229 24.290 275.906 13.700 5.560
0.929 5.144 23.696 271.575 14.900 5.670
0.964 5.076 23.562 266.106 15.700 5.760
0.999 4.966 23.071 262.337 16.300 5.650
1.039 4.639 22.479 255.724 16.700 5.950
1.074 4.673 21.712 246.919 19.500 6.040
1.109 4.491 20.667 237.597 20.500 6.150
1.139 4.263 19.606 225.477 20.600 6.260
1.164 4.062 16.966 215.971 21.900 6.350
1.169 3.666 16.056 205.647 21.600 6.450
1.214 3.626 16.649 192.044 22.600 6.560
1.234 3.404 15.620 160.269 22.000 6.650
1.254 3.166 14.613 166.617 22.700 6.730
1.274 2.977 13.636 157.743 22.600 6.620
1.294 2.666 13.411 152.922 23.600 6.920
1.314 2.666 12.493 142.496 23.300 7.010
1.334 2.460 11.523 131.476 24.300 7.090
1.359 2.214 10.291 117.419 25.000 7.200
1.369 1.954 9.060 103.631 26.200 7.310
1.419 1.736 6.060 92.216 26.600 7.420
1.446 1.490 6.924 79.074 27.500 7.540
1.476 1.217 5.657 64.632 27.700 7.650
1.506 0.992 4.610 52.659 26.900 7.760
1.543 0.731 3.396 36.624 30.600 7.660
1.576 0.465 2.162 24.715 32.200 6.000
1.613 0.212 0.967 11.290 32.200 6.100
1.653 -0.059 -0.273 -3.121 179.900 6.230
1.693 -0.306 4.424 46.267 455.000 6.340
1.733 -o.527 -2.446 -26.041 451.600 6.440
1.776 -0.749 -3.464 419.672 451.300 6.560
1.626 -0.960 4.465 -51.102 450.600 6.670
1.676 4.142 -5.310 450.760 450.000 6.760
1.936 4.346 6.269 -71.785 450.700 6.690
1.997 4.510 -7.023 -60.459 450.300 9.000
2.062 4.666 -7.759 .66675 450.600 9.110
2.137 4.647 .6566 -98.439 450.500 9.220
2.222 -2040 -9.469 406.794 450.300 9.330
2.317 -2200 40.234 417.345 450.500 9.440
2.421 -2.396 41.146 427.763 450.100 9.540
2.546 -2.569 41.953 437.107 450.200 9.650
2.666 -2.751 42.602 446.911 450.600 9.750
2.655 -2.922 43.596 456.252 450.700 9.660
3.044 4.101 44.437 465.723 451.400 9.970

91

Good.
(US/cm)

2049.000
2085.000
2081.000
2081.000
2035.000
2043.000
2084.000
2088.000
2087.000
2072.000
2072.000
2080.000
2084.000
2084.000
2084.000
2088.000
2085.000
2089.000
2101.000
2103.000
2104.000
2099.000
2104.000
2112.000
2115.000
2114.000
2118.000
2122.000
2118.000
2125.000
2127.000
2129.000
2128.000
2131.000
2128.000
2127.000
2130.000
2135.000
2131.000
2138.000
2141.000
2148.000
2147.000
2151.000
2151.000
2157.000
2181.000
2187.000
2188.000
2170.000
2175.000
2183.000
2190.000
2205.000
2212.000
2225.000
2243.000
2288.000
2289.000
2314.000
2357.000
2397.000

Temp
(609 C)

34.300
34.200
34.200
34.200
34.300
34.300
34.200
34.200
34.100
34. 100
34.100
34. 100
34.100
34. 100
34.100
34.100
34.100
34.000
34.100
34.100
34.000
34.000
34.000
34.000
34.000
34.000
34.000
34.000
33.900
33.900
33.900
33.900
33.900
33.900
33.900
33.900
33.900
33.900
33.900
33.800
33.800
33.800
33.800
33.800
33.800
33.700
33.800
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.700
33.800
33.800
33.800

Acid (ml) 896. (ml) Total (ml)

0.018
0.029
0.029
0.029
0.003
0.000
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029
0.029

0.029

0.000
0.029
0.032
0.047
0.000
0.000

0.395

0.417
0.429
0.442
0.457
0.474
0.493
0.514
0.539
0.587
0.801
0.839

-

200.018
200.057
200.060
200.075
200.003
200.000
200.097
200.122
200.145
200.164
200.177
200.185
200.192
200.198
200.203
200.209
200.215
200.222
200.229
200.238
200.243
200.250
200.257
200.265
200.272
200.279
200.285
200.290
200.295
200.300
200.304
200.308
200.312
200.318
200.320
200.324
200.329
200.335
200.341
200.347
200.353
200.359
200.388
200.373
200.380
200.388
200.398
200.404
200.413
200.423
200.433
200.445
200.457
200.470
200.485
200.502
200.521
200.542
200.587
200.595
200.829
200.867

Table 24: Potentiometric Titration (POTN702.esa), 0.5 vol. % SHS Composite

 

{TiszAle3}, 1x104“ M KN03
ESA Dyn Mob
Net (meql1) (mPe'MN) (m‘Z/V’s) Zeta (mV)
4.968 0.354 1.525 34.942
4.963 0.326 1.412 32.408
4.958 0.311 1.340 30.881
4 .953 0.298 1.273 29.330
4 .948 0.278 1.198 27.856
4.943 0.263 1.131 26.144
4.938 0.253 1.090 25.192
4.933 0.243 1.048 24.202
4.928 0.233 1.005 23.341
4.923 0.228 0.984 22.862
4.918 0.221 0.952 22.168
4.913 0.210 0.905 21.077
4.908 0.204 0.877 20.491
4.903 0.196 0.844 19.740
4.898 0.194 0.834 19.548
4.888 0.186 0.801 18.781
4.873 0.178 0.768 18.019
4.648 0.189 0.730 17.151
4.813 0.164 0.708 18.671
4.768 0.153 0.859 15.518
4.714 0.148 0.837 15.034
4.654 0.142 0.612 14.458
4.579 0.133 0.573 13.579
4.489 0.127 0.547 12.978
4.384 0.128 0.550 13.059
4.270 0.121 0.522 12.403
4.135 0.123 0.530 12.619
-0.970 0.120 0.519 12.382
-0.791 0.123 0.529 12.652
-0.547 0.127 0.546 13.050
-0.253 0.129 0.558 13.340
0.106 0.137 0.590 14.137
0.489 0.148 0.838 15.297
0.947 0.158 0.875 18.188
1.454 0.167 0.721 17.342
2.025 0.181 0.781 18.778
2.828 0.192 0.831 19.979
3.297 0.198 0.858 20.660
4.011 0.209 0.904 21.879
4.695 0.222 0.981 23.301
5.388 0.228 0.990 23.990
8.078 0.235 1.022 24.791
8.769 0.244 1.062 25.800
7.438 0.250 1.085 28.434
8.024 0.242 1.054 25.881
8.891 0.242 1.053 25.649
9.174 0.243 1.080 25.658
9.882 0.239 1.042 25.447
10.180 0.234 1.021 24.946
10.712 0.235 1.027 25.129
11.289 0.243 1.060 25.974
11.928 0.249 1.068 28.879

Phase
(«9)

142.800
142.400
142.500
142.800
143.700
142.000
142.500
142.400
142.100
142.100
142.400
141.300
141.500
141.300
140.900
141.300
140.900
139.800
139.100
138.300
138.500
138.100
135.800
133.500
133.500
132.800
131.500
130.400
129.900
131.200
128.800
129.400
129.100
127.800
127.800
128.400
128.000
127.000
127.000
128.500
124.800
124.200
122.500
120.700
118.500
115.500
112.700
110.700
107.400
105.900
102.700
102.200

pH (units)

4.830
4.880
5.030
5.180

9.030

9.570

9.910

92

Good.
(US/cm)

818.000
822.000
829.000
832.000
835.000
837.000
844.000
844.000
850.000
850.000
858.000
880.000
859.000
862.000
882.000
885.000
884.000
889.000
874.000
878.000
880.000
885.000
893.000
902.000
908.000
920.000
933.000
948.000
983.000
990.000
1021.000
1057.000
1100.000
1144.000
1198.000
1281.000
1320.000
1385.000
1454.000
1528.000
1598.000
1858.000
1732.000
1801 .000
1881.000
138.000
2041.000
2133.000
2240.000
2351.000
2486.000
2858.000

Temp
(609 C)

Acid (ml)

8666 (ml)

2.807

Total (m!)

 

200 398
200.399
200.400
200.401
200.402
200.403
200.404
200 405
200 406
200.407
200.408
200.409
200.410
200.411
200.412
200.414
200 417
200.422
200.429
200.438
200 449
200.481
200.478
200.494
200 51 5
200.538
200.585
200.598
200.834
200.883
200.742
200.814
200.891
200 983
201.085
201.200
201.321
201.458
201.800
201.738
201.878
202.017
202.157
202292
202411
202.548
202.844
202.747
202.848
202.958
203.073
203.203

Table 25: Potentiometric Titration (POTN705.esa), 0. 5 vol. % SHS Composite

{TiB2/A1203}, 1310‘1 M KNO;

Net
(meal)

-2.148
-2.138
-2.133
-2.128
-2.123
-2.118
-2.1 13
-2.108
-2.103
-2.098
-2.093
-2.088
-2.083
-2.078
-2.073
-2.088
-2.083
-2.058
-2.048
-2.028
4 .998
4 .958
4 .908
4 .853
4 .788
4 .714
4 .829
4 .529
4 .414
4 .275
4. 120

-0. 827

ESA
(mPa'MN Dyn Mob
(m‘2N‘6) Zeta (mV)

) .

0.171

1.125

17.542

19. 729
21.298
21.758
22.781
23.991
24.929
25.545
28.287
27.091
28.034
26.523
25.941
25.318
24.714
24.887
24.844
25.010
25.727

Phase
(609)

143. 3%

142. 7%
142.5%
142.1%
141.3%
140.800
140.8%
140.4%
140. 9%
141.2%
139.7%
139.500
138. 9%
137. 8%
1%. 5%
134. 2%
131.800
130.100
128.2%
124.0%
121.4%
118.8%
117.4%
115.2%

Cond.

PH (Um) (uS/cm)

93

Temp
(deg C)

Add (ml) 8666 (ml) Total (ml)

 

APPENDIX C

Green Body Density Measurements

94

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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SN 90.6 86 3.. 0.3 x2: 8.” n. v 9:8 852
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8.« m8. .«.. «8 8.0. oz 0.. m« . 9:8 8.802
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8.. ammo «m... .8 «to. 02 m.. o« . 9:8 8.582
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APPENDIX D

Sintered Density Measurements

100

able 29: Sintered Measurements for the Three

Condition/1m
T

in

in Water

‘YYEQQ‘. in Water

ConditioerBOOC
T

Condition/1m SHS TiBJAleoa-SG
Temperature 203

in
in Water

in Water

Condition/1800C SHS TiBjAlcoa-SG
Temperature

in Water
in Water

in

in Water

in Water

in Water

Condition/1m SHS TiBJAKP-SO
Temperature A120,

1

74
.83

 

101

APPENDIX E

Conductivity Measurements

102

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 30: Conductivity Measurements
Direction SHS '1'in Alcoa SHS TiB2] AKP—
Green Body Conductivity on Sample SHS Composite 86 A120, 50 A1203
ms MWmctions No Conductivity No Conductivity No Conductivity
General Sintered Body Direction SHS '11le Alcoa SHS '1'in AKP-
Conductivity on Sample SHS Composite 86 A1203 50 A1203
All Processing CEHHI'ons All (firedions Conductive uctive uctive
e: erednié to m
Specific Sintered Body
Conductivities Ma (1700 Direction 511an Alcoa SHS 1131/ AKP-
°C) on Sample SHS Composite 56 “2°: 50 A1203
~l-"EG Squace 0.2 0.2 "'
Across
broadest point
of sample 1 .3 0.2 0.2
pH 4 u ce 0.2 " 0.2-1.8
Across
broadest point
ofsample 0.7-42 0.3 3.0
pH 7 or 7.5 urfaoe 0.2 0.1-‘0: 0.3-9k“
Across
broadest point
of sample 1.1-9kfl' 0.2 0.2-6
m fidfice 0.2 0.1 no data
Across
broadest point
of sample 0.4-3.5 varies 0.5-1040 no data
'Fluctuates - multimeter will not come to rest
top surface had light and dark areas; multimeter readings ranged
from 0.1-0.9 but went as high as 162.47 and down to 137+
mulfiméfer will not come to rest I
variation over top surface: matte black 0.6. grey powdery 7.4.
mafia black to grey 72.1; bottom 0.2
Specific Sintered Body
Conductivities Ma (1800 Direction sns “my Alcoa sns my ma-
°C) on Sample SHS Composite 56 A1203 50 A1203
PET Sfiraoe 0.3-1.1 0.2 None
Across
broadest point
olsample 0.5-2.1‘ 0.4 2.2
pH 4 Surface 0.3—0.9 3.4‘ 3.3-4.0
Across
broadest point
ofsample 0.8-4.1’ 5.0’
-1 (very smelt.
rinegular shaped
pH 7 or 7.5 Surtace 0.2 sample) 3.4‘
Across
broadest point
of sample 0.6-4.1’ 1.5’ 2.4’
2.9 (very small
pH 8 or 9 Surface 0.5 0.2 sample)
Across
broadest point
of sample 0.4 J_0.5 1.2
’Fluctuates-multimeter will not come to rest

 

 

103

 

APPENDIX F

Microhardness Measurements

104

Table 31: Microhardness Measurements (Vickers (HV)).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Composite
System SHS AKP-50 ALCOA
mm“! 5/17; AVG 1109;
Cum" PEG 1700 C NO DATA 270 STD DEV 0/5
3/15; 874 AVG; 90
1800 C NO DATA STD DEV NO DATA
1/12; 1382 "AVG"; 0
pH 4 1700 c STD DEV 0/6 0/8
5/15; 913 AVG; 222 5/20; 679 AVG; 368
1800 c NO DATA STD DEV STD DEV
2/15; 1426 AVG; 34 3/15; 901 AVG; 126
pH 7 or 7.5 1700 c STD DEV NO DATA STD DEV
5/20; 915 AVG; 356 4/19; 846 AVG; 238 10/20; 860 AVG;
1800 C STD DEV STD DEV 293 STD DEV
3/16; 633 AVG; 224 8/20; 747 AVG; 351
pH 8 or 9 1700 c NO DATA STD DEV STD DEV
10/26; 974 AVG;
1800 c NO DATA N/A 234 STD DEV
11/54; 1892 AVG;
None Hot Pressed 175.1 STD DEV N/A N/A

 

'Data: valid measurements/attempted measurements (# I if); average of valid #’s
(AVG); standard deviation for valid #’s (STD DEV); Note that HV =GPa x 102

105

 

APPENDIX C

Porosity Measurements from Backscatter SEM Micrographs

106

Reconstruction of three-dimensional information about the pore structure was
determined by a direct a lineal analysis of backseatter SEM micrographs. This direct
method was sufficient for estimations to compare between micrographs, but was not as
detailed as would be expected by instrumental analysis. The definition of porosity was
[EMSE 1986, p. 3832]:

LP

m ‘2‘”

where Lp and L_, are the total lengths of lines lying in pores and matrix of a series of lines

across the micrograph (Figure 23).

  

: " ‘ » - H g
Figure 23: Backseatter SEM micrograph with lineal analysis, after EMSE [1986, p.
3832]

Although it was of no consequence whether the lines were regularly or randomly
distributed, a regular pattern is typical of instrumental analysis. and was used in these
direct measurements. Further, this type of analysis is independent of magnification
[EMSE 1986, p. 3832], which was convenient since micrographs of various origins were

compared in this study.

107

Table 32: Porosity Measurements from Backscatter SEM Micrographs

 

 

 

 

 

 

 

 

 

 

Porosity (a) s = L,/(L,+L,)
Composite Recipe Processing Condition
SHS {'TiB,/Al,0,} PEG (Figure 2101))
Line 1 Line 2 Line 3 Line 4
Lp (mm) Ls (mm) Lp (mm) Ls (mm) Lpunm) Ls (mm) Lp (mm) Ls (mm)
0 55 ll 17 18 18 2 48
2 3 2 75 8 6 5 l I
10 3 4 12 18 6 2
3 13 1 22 7 5
4 2 6 3 20
5 8
24 84 17 92 39 7O 23 86
108 109 109 109
s = 23.68%
SHS {TileAl103} pH 4 (Flgure 21(b))
Line 1 Line 2 Line 3 Line 4
LP (mm) L, (mm) LptmIn) L, (min) L9 (mm) L: (mm) Ln (mm) L, (mm)
30 42 5 6 11 19 16 27
5 12 8 31 1 13 58
1 l 6 8 57
1 22
6 7
35 65 26 74 12 89 16 85
100 100 101 101
6 = 22. l4°/o
SHS ff 13:/A1203} pH 7 (Film 21(9))
Line 1 Line 2 Line 3 Line 4
Lp (mm) L11(n11n) Lp(1'r1m) Ls (mm) Lp (mm) Ls (mm) I-'p (mm) Ls (mm)
2 25 12 7 15 2 17 47
35 15 3 8 3 56 5 5
7 12 7 6 l 2 15 l l
l l l 7 18 8 5 3
5 3O 2
6 ll
4
55 52 34 73 39 68 42 66
107 107 107 108
6 = 39.639/0

 

 

108

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SHS {TiB,/A1,0,) pH 9 (Figure 21(d))
Line 1 Line 2 Line 3 Line 4
Lp (turn) Ls (mm) Lp (min) L: (mm) Lp (mm) L: (mm) Lp (min) Ls (mm)
19 10 6 5 2 l6 7 44
14 22 8 63 10 10 6 4
10 23 1 1 3 5 15 7 24
7 9 7 3 6 30 10 5
4 2 20 7
6
50 64 42 76 23 91 37 77
114 118 114 1 14
a = 33.04%
SHS TileAKP 50 A50, PEG (Figure 21(e))
Line 1 Line 2 Line 3 Line 4
LP (mm) Ls (mm) Lptmrn) Ls (mm) LNM) Ls (mm) Loom» Litmml
7 10 5 5 4 15 5 43
76 10 61 2 67 10 12
12 5 23
7 86 15 78 6 87 15 78
93 93 93 93
a = 11.56%
SHS Tug/AKP so A110, pii 4 (Figure 21(1))
Line 1 Line 2 Line 3 Line 4
Lorain) L-(mm) Loin-m) Lin-uni LNM) L- (m) LPtIIun) L, (m)
10 8 7 54 10 2 4 32
9 7 10 5 5 10 5 l9
6 31 15 10 20 4 25
7 ll 5 21 2
2 8
32 59 32 59 30 61 13 78
91 91 91 91
8 = 29.40%
SHS Tug/AKP so AI,O, pH 7.5 (Figure 21(g))
Line 1 Line 2 Line 3 Line 4
L01mm) L, (m) Lptmm) Lurmm) LNM) Lsrmm) Lpimm) L: (m)
20 51 l 12 8 5 5 9
4 9 4 20 9 28 6 7
7 2 30 7 30 3 41
11 ll 4 2 6
12
24 67 18 73 24 67 16 75
91 91 91 91
E = 22.530/0

 

109

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

sus TiB,/AKP 50 A50, pH 8 (Figure 2101))
Line 1 Line 2 Line 3 Line 4
LPtrnIn) Ls (mm) Lptmrn) Lstmm) LP (mull Luann) LPtIMI) Lilmm)
8 65 3 5 3 15 7 36
3 15 9 l9 3 70 13 20
55 15
ll 80 12 79 6 85 20 71
91 91 91 91
a = 13.46%
sus TiB,/A1eoe SG 141,0, PEG (Figure 21(i))
Line 1 Line 2 Line 3 Line 4
Lp(mrn) Ls (mm) Lp(mm) l-’s(mm) Lp (min) Ls (mm) Lp(mm) l~‘s(mm)
4 l3 3 15 2 12 3 41
4 16 l 20 7 21 5 l7
1 18 1 20 6 12 6 42
2 10 6 18 7 15
2 17 6 13 2 l8
2 18 l 10 10
7
15 99 18 96 24 88 14 100
114 114 112 114
a = 15.64%
SHS TiB,/Alcoa SG Ago, pH 4 (Figure 21(1))
Line 1 Line 2 Line 3 Line 4
Lp (mm) Ls (mm) Lp(ri'irn) I-’ii(mm) Lp (mm) Ls (mm) Lp(mm) L8(mm)
3 8 1 l3 4 l7 3 2
1 5 l 4 l 10 l 12
1 52 95 1 33 l 22
2 4 5 35 l 44
l 10 8 2 15
4 9 ll
13
12 101 2 112 ll 103 8 106
113 114 114 114
6' = 7250/0

 

110

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SHS TileAIcoa 86 A110, pH 7 (Figure 21(k))
Line 1 Line 2 Line 3 Line 4
I4p (mm) Ls (mm) Lp(mm) Luann) Lp(rnm) Lr(mm) Lptmru) Lstmm)
3 5 2 5 1 3 4 5
2 32 2 32 l 6 I 4
l 23 1 70 4 60 4 32
1 36 2 1 5 2 18
11 5 15 5 3
3 2 2 4
l 3 1 25
4 3
7 107 5 109 16 98 19 94
114 114 114 113
a = 10.33%
SHS TiB,/Alcoa SG A120, pH 8 (Figure 21(1))
Line 1 Line 2 Line 3 Line 4
LPtmml Ls (mm) Lptmm) Litmm) Lotion!) Lit-um) Lptmm) LItmm)
1 31 1 3 4 15 2 12
2 31 1 6 2 65 4 29
1 6 3 16 28 2 48
1 20 2 22 17
21 2 35
23
5 109 9 105 6 108 8 106
114 114 114 114
s = 6.14%
l-lotPressed
"Continuous"
Siis {TiB,/Al,0,} Microstructure
Line 1 Line 2 Line 3 Line 4
Lp(mm) Ls (mm) Lp(mm) Lstrnrn) Lptmm) L8(mm) Lp(nun) LHmm)
1 16 7 5 15 52 3 20
4 28 1 5 2 91 6 10
6 17 4 5 14 15 4 47
2 3| 6 29 8 5 35
6 45 3 5 6 4
41 4 23 56
2 4
3 2
4 34
2 10
17 22
19 178 53 144 31 166 24 172
197 197 197 196
6‘ = 16.14%

 

 

111

 

Table 33: Summary of Lineal Analysis Data for Porosity Measurements from

 

 

 

 

 

 

Backseatter SEM Micrographs
Processing Condition SHS {TiB1/A1103} SHS TiB2/AKP 50 A110, SHS TileAlcoa SG A120,
PEG 23.7% 1 1 .6% 15.6%
Dispersion 22.1% 29.4% 7.3%
Coagulation 39.6% 22.5% 10.3%
Heterocoagulation 33.0% 13 .5% 6.1%
Hot Pressed 16.1% N/A N/A

 

 

 

 

 

112

 

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