- •Preface to the Second Edition
- •Preface to the First Edition
- •ACKNOWLEDGEMENTS
- •Contents
- •1.1 EXERCISES, QUESTIONS, AND PROBLEMS
- •2.1 INTRODUCTION
- •2.2 CORROSION BY LIQUIDS
- •2.2.1 Introduction
- •2.2.2 Crystalline Materials
- •Attack by Molten Glasses
- •Attack by Molten Salts
- •Electrochemical Corrosion
- •Attack by Molten Metals
- •Attack by Aqueous Media
- •2.2.3 Glasses
- •Bulk Glasses
- •Fiber Glass
- •Bioactive Glass
- •2.3 CORROSION BY GAS
- •2.3.1 Crystalline Materials
- •2.3.2 Vacuum
- •2.3.3 Glasses
- •2.4 CORROSION BY SOLID
- •2.5 SURFACE EFFECTS
- •2.5.1 Surface Charge
- •2.5.2 Porosity and Surface Area
- •2.5.3 Surface Energy
- •2.6 ACID/BASE EFFECTS
- •2.7 THERMODYNAMICS
- •2.7.1 Mathematical Representation
- •2.7.2 Graphical Representation
- •2.8 KINETICS
- •2.9 DIFFUSION
- •2.10 SUMMARY OF IMPORTANT CONCEPTS
- •2.11 ADDITIONAL RELATED READING
- •2.12 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •3.1 INTRODUCTION
- •3.2 LABORATORY TEST VS. FIELD TRIALS
- •3.3 SAMPLE SELECTION AND PREPARATION
- •3.4 SELECTION OF TEST CONDITIONS
- •3.5 CHARACTERIZATION METHODS
- •3.5.1 Microstructure and Phase Analysis
- •Visual Observation
- •Optical Microscopy
- •X-ray Diffractometry
- •Transmission Electron Microscopy
- •3.5.2 Chemical Analysis
- •Bulk Analysis
- •Surface Analysis
- •3.5.3 Physical Property Measurement
- •Gravimetry and Density
- •Porosity-Surface Area
- •Mechanical Property Tests
- •3.6 DATA REDUCTION
- •3.7 ADDITIONAL RELATED READING
- •3.8 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •4.1 INTRODUCTION
- •4.2 ASTM STANDARDS
- •4.2.16 Permeability of Refractories, C-577
- •4.2.26 Lead and Cadmium Extracted from Glazed Ceramic Surfaces, C-738
- •4.3 NONSTANDARD TESTS
- •4.4 ADDITIONAL RELATED READING
- •4.5 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •5.1 ATTACK BY LIQUIDS
- •5.1.1 Attack by Glasses
- •Alumina-Containing Materials
- •Zircon
- •Zirconia
- •Carbides and Nitrides
- •5.1.2 Attack by Aqueous Solutions
- •Alumina
- •Silica and Silicates
- •Concrete, Cement, Limestone, Marble, and Clay
- •Zirconia-Containing Materials
- •Superconductors
- •Titanates and Titania
- •Transition Metal Oxides
- •Carbides and Nitrides
- •5.1.3 Attack by Molten Salts
- •Oxides
- •Carbides and Nitrides
- •Superconductors
- •5.1.4 Attack by Molten Metals
- •5.2 ATTACK BY GASES
- •5.2.1 Oxides
- •Alumina
- •Alumino-Silicatcs
- •Magnesia-Containing Materials
- •Zirconia
- •5.2.2 Nitrides and Carbides
- •Silicon Nitride
- •Other Nitrides
- •Silicon Carbide
- •Other Carbides
- •5.2.3 Borides
- •5.2.4 Silicides
- •5.2.5 Superconductors
- •5.3 ATTACK BY SOLIDS
- •5.3.1 Silica
- •5.3.2 Magnesia
- •5.3.3 Superconductors
- •5.3.4 Attack by Metals
- •5.4 ADDITIONAL RELATED READING
- •5.5 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •6.1 INTRODUCTION
- •6.2 SILICATE GLASSES
- •6.3 BOROSILICATE GLASSES
- •6.4 LEAD-CONTAINING GLASSES
- •6.5 PHOSPHORUS-CONTAINING GLASSES
- •6.6 FLUORIDE GLASSES
- •6.7 CHALCOGENIDE-HALIDE GLASSES
- •6.8 ADDITIONAL RELATED READING
- •6.9 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •7.1 INTRODUCTION
- •7.2 REINFORCEMENT
- •7.2.1 Fibers
- •7.2.2 Fiber Coatings or Interphases
- •7.2.3 Particulates
- •7.3 CERAMIC MATRIX COMPOSITES
- •7.3.1 Oxide-Matrix Composites
- •Al2O3-Matrix Composites
- •Other Oxide-Matrix Composites
- •7.3.2 Nonoxide-Matrix Composites
- •Si3N4 Matrix Composites
- •SiC-Matrix Composites
- •Carbon-Carbon Composites
- •Other Nonoxide Matrix Composites
- •7.4 METAL MATRIX COMPOSITES
- •7.5 POLYMER MATRIX COMPOSITES
- •7.6 ADDITIONAL RELATED READINGS
- •7.7 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •8.1 INTRODUCTION
- •8.2 MECHANISMS
- •8.2.1 Crystalline Materials
- •8.2.2 Glassy Materials
- •8.3 DEGRADATION OF SPECIFIC MATERIALS
- •8.3.1 Degradation by Oxidation
- •Carbides and Nitrides
- •Oxynitrides
- •8.3.2 Degradation by Moisture
- •8.3.3 Degradation by Other Atmospheres
- •Carbides and Nitrides
- •Zirconia-Containing Materials
- •8.3.4 Degradation by Molten Salts
- •Carbides and Nitrides
- •Zirconia-Containing Materials
- •8.3.5 Degradation by Molten Metals
- •8.3.6 Degradation by Aqueous Solutions
- •Bioactive Materials
- •Nitrides
- •Glassy Materials
- •8.4 ADDITIONAL RELATED READING
- •8.5 EXERCISES, QUESTIONS, AND PROBLEMS
- •REFERENCES
- •9.1 INTRODUCTION
- •9.2 CRYSTALLINE MATERIALS—OXIDES
- •9.2.1 Property Optimization
- •9.2.2 External Methods of Improvement
- •9.3 CRYSTALLINE MATERIALS—NONOXIDES
- •9.3.1 Property Improvement
- •9.3.2 External Methods of Improvement
- •9.4 GLASSY MATERIALS
- •9.4.1 Property Optimization
- •9.4.2 External Methods of Improvement
- •REFERENCES
- •Glossary
- •Epilog
8 |
Chapter 1 |
1.1EXERCISES, QUESTIONS, AND PROBLEMS
1.List the different fields that an engineer might want to study to be proficient in evaluating corrosion problems.
2.List all the various courses taught in a standard ceramic engineering curriculum that might contain information related to corrosion.
3.Discuss whether it is more important to know whether a material will corrode or how long it will last.
4.Discuss several applications where the corrosion is a beneficial factor rather than a problem. Find several applications not listed in the text.
5.Develop an equation that represents all the various factors involved in determining the total cost of a particular corrosion problem. Pick a particular product and try to find as much information as possible concerning the actual costs.
6.Discuss the relationship of erosion to corrosion and how it can be a major actor in the overall process of corrosion.
Copyright © 2004 by Marcel Dekker, Inc.
2
Fundamentals
Everything should be made as simple as possible, but not simpler.
ALBERT EINSTEIN
2.1 INTRODUCTION
Corrosion of ceramics can take place by any one or a combination of mechanisms. Various models have been proposed to describe these mechanisms, several of which will be discussed below. In general, the environment will attack a ceramic, forming a reaction product. The reaction product may be either solid, liquid, gas, or any combination of these. This reaction product may remain attached to the ceramic or it may be fugitive, in the case when gaseous species make up the reaction product, or it may be a combination of both. When
9
Copyright © 2004 by Marcel Dekker, Inc.
10 |
Chapter 2 |
the reaction product remains as a solid, quite often it forms a protective layer toward further corrosion. At other times, for example, if the reaction product is a combination of solid and liquid, this reaction layer may be removed through the process of erosion. Thus to analyze corrosion, one must have some idea of the type of processes that are in operation. When the reaction product remains as an intact interfacial layer, analysis is relatively easy. When gaseous species are formed, the consumption of the ceramic manifests itself as a weight loss. An understanding of the mechanism, however, requires analysis of the evolved gases. Many times, the interface formed is very porous and/or friable requiring special care in preparing samples for analysis. Because of the various processes that may take place during corrosion, there is no one general model that can explain all cases of corrosion. In addition, a single ceramic material will react differently to different environments and thus there is no single explanation for the corrosion of a particular material for all environments. It is also true that the manufacturing history of a ceramic material will affect its performance. This may manifest itself, for example, as a low corrosion-resistant grain boundary phase or a pore size distribution that greatly increases the exposed surface area to corrosion. Thus it should be obvious that a simple allencompassing general theory of corrosion of ceramics does not exist and, because of the nature of corrosion and ceramics, will most likely never exist. There does, however, appear to be a common thread connecting all the various studies that have been reported. That is, corrosion is dependent upon the structural characteristics of the material. The more compact or tightly bonded materials corrode less whether they are glasses or crystalline materials. Thus it appears that if a general theory is to be developed, a comprehensive investigation of single crystals and some structurally well-characterized glasses should be investigated.
Corrosion, being an interfacial process, requires a thorough understanding of the surface structure of the material being corroded. Thus the study of single crystals is the best method
Copyright © 2004 by Marcel Dekker, Inc.