Electric Contacts

This book is a completely revised and rewritten edition of "Electric Contacts Handbook" published in 1958. A large number of new in vestigations are considered, and many of the basic theories are revised in detail and even in general. The body of information had to be limited as it was not advisable to increase the volume of the book. In particular, no attempt was made to cover all of the practical applications. They appear as examples following concentrated explanations of basic phenomena. As in several branches of technology, the solutions of problems ari sing in the field of electric contacts involve insight into various disci plines of physics. It is feit that reviews of some of those topics, especi ally adapted to electric contact phenomena, are welcome to many readers. For example, chapters have been devoted to the structure of carbon, the band theory of electric conduction in solids, certain pro blems in statistics, and the theory of the electric arc. As regards arc problems, new ideas have been introduced. In order to make the main text less cumbersome, such reviews are presented as appendices. Throughout this edition, the mksa-unit system is used in accord with the latest recommendation for standardization of units in scientific and technical writings. The chapter "History of Early Investigations on Contacts" forming Part IV in the preceding edition of 1958 has not been repeated in this book.

I. Stationary Contacts. - II Thermal Contacts. - III Sliding, Contacts. - IV Electric Phenomena in Switching Contacts. - Appendices. - § I. Elasticity, plasticity and hardness. - A. Introduction. - C. Plastic deformations. Dislocations. - D. Mathematics of plastic yielding. - E. Indentation in an isotropic semi-infinite body, produced by a spherical indenter (ball). - F. The ball and pyramid indentation tests. Hardness. - G. Influence of friction on the indentation. - H. Diffusion effects. - I. The work consumed by a plastic deformation. Examples. - § II. Electronic conduction in solids. - A. Introduction. - B. General concepts concerning conduction. - C. Quantization of the electrons in a crystal and the constitution of a band. - D. Influence of the temperature on the distribution (or partition) of electrons on cells in metals. - E. Current carriers in semiconductors. - F. Mobility of current carriers. Resistance. - G. Surface potential barrier of a metal. Thermionic emission of electrons. - I. Metal-semiconductor contact. - A. Heat capacity. - B. Thermal conduction. - § IV. Probability. Noise. - A. Normal distribution. - B. Probability paper. - D. Electrical noise. - § V. Structure, electrical and thermal conductivity of carbons 404 A. Introduction. Graphite lattice. - B. Carbon grades. 406 C. Graphitization. - D. Electrical conductivity of carbons. - E. Heat conductivity of carbons. - § VI. Hydrodynamic or thick film lubrication. - § VII. Metal whiskers 417 A. Whiskers formed from the solid metal. - B. Whiskers rapidly formed from metal vapor. - C. Mechanical and magnetic properties of whiskers. - D. Metallic dendrites in semiconductors. - § VIII. Some fundamental formulas concerning electric discharges. - A. Introduction. Kinetic fundamentals. - B. Drift velocity. - D. Plasma. - E. Current in vacuumrestricted by the space charge of the current carriers. - § IX. Theory of the electric arc. - A. Introduction. - B. Cathode layer. - C. Emission of primary electrons from the cathode. - D. The ion current in the cathode layer. - F. Summary of the results presented in Table (IX, 5). - G. Power balance at the cathode. - H. Power balance at the anode. - I. Voltage-current characteristics of arcs. - J. Pinch effect. - § X. Tables. - § XI. Diagram XI in two copies, one detachable. - Author and literature index. - Errata.