Nonmetals

Metals and Alloys

Defect and Diffusion Forum Vol. 9

This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.

This book outlines, with the help of several specific examples, the important role played by absorption spectroscopy in the investigation of deep-level centers introduced in semiconductors and insulators like diamond, silicon, germanium and gallium arsenide by high-energy irradiation, residual impurities, and defects produced during crystal growth. It also describes the crucial role played by vibrational spectroscopy to determine the atomic structure and symmetry of complexes associated with light impurities like hydrogen, carbon, nitrogen and oxygen, and as a tool for quantitative analysis of these elements in the materials.

This volume is the proceedings of the NATO Advanced Study Institute, "Diffusion in Materials", held at "Centre Paul Langevin", Aussois, during March 12-25, 1989. There were 105 participants of whom 24 were lecturers and members of the international advisory committee. In addition to the participants from NATO countries, a small number of participants came from Australia, Hungary, Poland and Tunisia. The principal aim of the organizing committee was to bring together scientists of wide interest and expertise in the field of diffusion and to familiarize the young workers in material science with the wide range of theoretical models and methods and of experimental techniques . The Institute was concerned with the study of diffusion and related phenomena in solids which are at the cutting edge of novel technologies. The discussion of basic theories of defects in solids and their transport, with their applications in the understanding of diffusion processes in "simple solids" was followed by the wide range of current theoretical models and methods, experimental techniques and their potential. The lectures on the diffusion in specific materials included : metals, dilute and concentrated alloys, simple and compound semiconductors, stoichiometric and non-stoichiometric oxides, high-Tc compounds, carbides, nitrides, silicates, conducting polymers and thin films, ionic, superionic, amorphous and irradiated materials.

Liquid metal technology has been the subject of an impetuous development in the recent decades, mainly due to the application of liquid met als in nuclear techniques. The technological development has been supported by studies of the basic physical-chemical properties of liquid metals: One major concern is the material behaviour in contact with the liquid metals, corrosion and the possible deterioration of metallic and ceramic materials which are in use as constructional or functional materials in such systems. Since the corrosion is in many cases not only a simple dissolution process, the chemical background of such processes had to be studied. Such studies included the determination of solubilities of metals and non-metals in liquid metals, the measurement of thermodynamic data of dissolved materials and of chemical equilibria. Several formerly unknown chemical compounds are formed in liquid metal~ lnd are only stable in this environment. The research and deve\opment devoted to the fission reactor techniques were more or less completed in several countries, further work is in progress in some countries in which the interest in fast breeder reactors arose recently. Even the worldwide program on fusion reactor technology is related to liquid metals, and severallaboratories are now contributing to this new technology.

Diffusion, the movement of atoms in a material, is an integral part of many metallurgical and materials treatment processes. Understanding diffusion mechanisms helps to control and improve materials properties. This book offers a comprehensive overview of diffusion in the synthesis and analysis of materials (metals and non‐metals) from the fundamentals through applications. Discusses defects in materials, fundamentals of the diffusion process, and different diffusion mechanisms active in metallic alloys Describes diffusion within non‐metallic materials, including ceramics, polymers, and semiconducting materials, with special emphasis on silicon Covers diffusion along high‐energy paths, short‐circuiting diffusion, such as grain boundaries, dislocations, and materials surface Explores diffusion under thermal and electrical gradients and explains how this information is useful for materials purification Details the application of diffusion on carbides during the thermal and thermomechanical treatments of steels Includes problems and solutions for each chapter to reinforce reader’s comprehension Written with less emphasis on complex mathematical equations, this text is accessible to researchers and students in materials, mechanical, and related engineering disciplines studying the phenomenon of diffusion in materials and its application in the engineering of materials.