Organic Additives and Ceramic Processing: With Applications in Powder Metallurgy, Ink, and Paint

323 Pages·1995·10.75 MB·English

by  Daniel J. Shanefield (auth.)

ORGANIC ADDITIVES AND
CERAMIC PROCESSING
With Applications in
Powder Metallurgy, Ink, and Paint
ORGANIC ADDITIVES AND
CERAMIC PROCESSING
With Applications in
Powder Metallurgy, Ink, and Paint
by
Daniel J. Shanefield
Rutgers University
.
.,
~
Springer Science+ Business Media, LLC
Library of Congress Cataloging-in-Publication Data
A C.I.P. Catalogue record for this book is available
from the Library of Congress.
ISBN 978-1-4757-6105-4 ISBN 978-1-4757-6103-0 (eBook)
DOI 10.1007/978-1-4757-6103-0
Copyright © 1995 by Springer Science+Business Media New York
Originally published by Kluwer Academic Publishers in 1995
Softcover reprint of the hardcover Ist edition 1995
AlI rights reserved. No part of this publication may be reproduced, stored in
a retrieval system or transmitted in any fom or by any means, mechanical,
photo-copying, recording, or otherwise, without the prior written permission of
the publisher, Springer Science+Business Media, LLC.
Printed on acid-free pap er.
Contents
PREFACE xi
1. INTRODUCTION 1
1.1 Historical Overview 1
Plasticity in Ancient and Modem Processing 1
Specialized Functions of Additives 3
Organic versus Inorganic 3
1.2 Typical Organic Additives 4
2. CHEMICAL AND PHYSICAL BONDING 8
2.1 Ordinary Bond Types 8
Electron Pair Orbitals 8
Ionic Bonds 10
Covalent Bonds 10
Physical Bonds 11
2.2 Lewis Acids And Bases 12
2.3 Hydrogen Bonds 14
2.4 Polarity 17
2.5 Radicals 18
2.6 Typical Structures 19
3. ORGANIC CHEMISTRY FUNDAMENTALS 20
3.1 The Naming System 20
Hydrocarbons 24
Alkyls 25
Alcohols 31
Carbonyl Compounds 33
Carboxylic Acids 35
v
vi Contents
Cyclohexane and Related Structures 36
Other Positional Tenns 41
Some Special Environmental Considerations 44
Cyclic Compounds With Double Bonds 47
Benzene Ring Compounds 49
Nitrogen Compounds 55
3.2 Reactions 56
A Few Important Reactions 56
Polymerization 59
3.3 Synthetic Polymers 62
Polyvinyls and Similar Thermoplastics 62
Thermosetting Polymers 70
High Performance Polymers 72
Copolymers 76
Characterization 76
3.4 Natural Carbohydrates 80
3.5 Hydrogen Bonds and Life 89
4. CERAMIC PROCESSING FUNDAMENTALS 91
4.1 The Process Steps From Powder To Ceramic 91
The Powder 92
The Slip 92
The First Shrinkage 94
Shaping the Green Body 95
~~~~ 100
The Fired Ceramic Product 107
4.2 Agglomerates 109
The Causes of Agglomeration 109
Types of Agglomerates 110
4.3 Optimum Surface Area 112
Contents vii
5. PARTICLE CHARACTERISTICS 113
5.1 The Packing Of Powders 113
The Sizes Needed for Closest Packing 113
The Sizes of Real Ceramic Powders 120
The Bell Shaped Curve 121
The Lognormal Distribution 123
Additional Porosity 124
Modified Particle Size Distributions 125
5.2 Surface Area Calculations 126
6. COLLOID SCIENCE, AS APPLIED TO CERAMICS 126
6.1 Adsorption 131
Bonding of the Adsorbate to the Powder 131
Specificity 136
Hydration of the Surface 139
6.2 Charged Particles In Suspension 140
Sources of Charge 140
The Double Layer 142
Measurement of the Charge 148
Changing the Charge 150
6.3 Stabilized Suspensions 153
Charge Repulsion 153
Steric Hindrance 155
6.4 Viscosity 158
6.5 Wetting 168
7. SOLVENTS 171
7.1 Predicting Solubility 172
Nonpolar Materials 172
Materials of Low Polarity 172
Highly Polar Materials 172
Polymers 174
viii Contents
7.2 Hydrogen Bonding Effects 176
Achieving High Solids Loading 176
Bubbles and Foam 177
Evaporation Rates for Fast Drying Solvents 178
Slow Drying Solvents 181
7.3 Safety 184
Flammability 184
Toxicity Regarding Dosage 186
Toxicity Regarding Animal Tests 191
Toxicity Regarding Human Exposure 194
Random Variations in Toxicity Studies 196
Use First, Test Later 200
Potential Damage to the Broader Environment 202
7.4 Cost 207
7.5 Chemical Attack on the Powder 209
8. DISPERSANTS AND OTHER SURFACTANTS 211
8.1 Tests For Effectiveness 211
Sedimentation Height 211
Minimum Viscosity 212
Maximum Solids Loading at Maximum Viscosity 213
Maximum Green Density 215
8.2 Commonly Used Detergents 218
Anionic Surfactants 218
Cationic Surfactants 221
Nonionic Surfactants 224
8.3 Inorganic Surfactants 226
8.4 Organic Deflocculants For Ceramics 229
Aqueous Systems 229
Nonaqueous Systems 236
High Solids Loadings 251
(7on ten ts ix
9. BINDERS 255
9.1 Burnout 259
General Considerations 259
Burning 261
Evaporation 264
Other Removal Methods 266
Nonuniform Burnout 267
9.2 Adhesion 269
9.3 Green Strength 271
Plasticizers 273
9.4 Other Additives 275
10. PROCESSING EXAMPLES 280
10.1 Dry Pressing 281
10.2 Injection Molding 283
10.3 Extrusion 284
10.4 Tape Casting 286
10.5 Slip Casting 290
APPENDIX I. GLOSSARY OF CERAMICS WORDS 291
APPENDIX II. WORDS USED IN COLLOID SCIENCE 297
APPENDIX III. INFORMATION SOURCES 302
INDEX 309
Preface
This volume is intended to be used as a textbook for teaching pur
poses and also as a reference source for working engineers. Therefore,
a wide range of subject matter must be covered, starting with funda
mental explanations for students, and extending to advanced applica
tions for development workers and factory problem-solvers. Such an
ambitious task is being attempted only because of the present lack of
resources which might otherwise fill the need.
The author planned the book for use as the primary text in an un
dergraduate course of the same title, which he teaches at Rutgers
University. However, the book could also be used as a supplementary
text for more general courses in ceramic processing.
Powder metallurgy, printing inks, and paints involve many of the
same organic additives as ceramic processing. These fields of technol
ogy are usually covered by college courses in metallurgy, materials
science, and chemical engineering. Apparently there is a need for bet
ter training in the specialized area of the organic additives used in
those fields. The formulators, for lack of better understanding and
confidence, often rely on simple waxes or acrylates, when a higher
level of technological knowledge could provide improved results. It is
intended that this book will be useful as a supplementary source of in
formation for those fields also, both as a self-teaching tool and for col
lege coursework.
Courses similar to the subject matter in this book are offered at insti
tutions of continuing education for working engineers, often in con
junction with professional societies. The students in such courses, in
xi
xii Preface
addition to trained engineers, include suppliers of materials to the in
dustries, market researchers, investors, and others who are peripheral
to the industries themselves. A continuing education course with the
same title as this book was taught by Dr. George Y. Onoda, Jr., and the
author starting in 1976. With periodic minor revisions, this course was
then taught by the author and other colleagues, twice each year up to
the present time, under the auspices of the Center for Professional
Advancement of East Brunswick, NJ, USA and of Amsterdam, The
Netherlands. In 1986, the author ended his 30 years in industry (spent
principally at AT&T) to accept a post as Distinguished Professor of
Ceramics Engineering at Rutgers University. He then began a college
course on this subject, which can be attended by either undergraduates
or graduate students. Notes from these various courses have been the
skeleton of this book.
Because there are so few schools in which students can specialize in
ceramics, many readers of this book (such as suppliers of additives) are
not likely to be knowledgeable in the fundamentals of ceramic science.
Therefore some attention is given to these principles, particularly
where they are the foundation for understanding the usage of the or
ganic additives. On the other hand, many specialists in ceramics
engineering have not been trained in the fundamentals of organic
chemistry. For that reason some attention is paid here to organic
chemistry concepts and technology. A logically configured pyramid of
simply-defined scientific words has been included throughout the text
and appendices. This extends downward to common words such as
"plastic" and "fluid." The extra attention to the explanations of simple
terminology results from the author's recent teaching experiences with
students in need of some remedial scientific training, and with students
from countries where English is not the main language spoken.
In addition to providing the essentials of the theoretical background,
it is among the author's goals to provide many of the practical details
of industrial operations, often gathered from his own experience in
ceramics factories. Case studies regarding specific problems are
presented, as well as decision tables that might help solve future
problems. It is hoped that readers will be able to take formulations
from this book, go to the laboratory, and immediately make a workable
ceramic product, at least as a running start for further developments.