MAGNETIC CERAMICS

oxide materials that exhibit a certain type of permanent magnetization called ferrimagnetism. Commercially prepared magnetic ceramics are used in a variety of permanent magnet, transformer, telecommunications, and information recording applications. This article describes the composition and properties of the principal magnetic ceramic materials and surveys their main commercial applications. Additional reading Materials on magnetic ceramics may be found in A.J. Moulson and J.M. Herbert, Electroceramics: Materials, Properties, Applications (1990); Larry L. Hench and J.K. West, Principles of Electronic Ceramics (1990); and the section titled Electrical/Electronic Applications for Advanced Ceramics, in Theodore J. Reinhart (ed.), Engineered Materials Handbook, vol. 4, Ceramics and Glasses, ed. by Samuel J. Schneider (1991), pp. 110566.A good introduction to ceramics in general is provided by David W. Richerson, Modern Ceramic Engineering: Properties, Processing, and Use in Design, 2nd ed., rev. and expanded (1992). The processing of both traditional and advanced ceramics is described in James S. Reed, Introduction to the Principles of Ceramic Processing (1988); I.J. McColm and N.J. Clark, Forming, Shaping, and Working of High Performance Ceramics (1988); George Y. Onoda, Jr., and Larry L. Hench, Ceramic Processing Before Firing (1978); and four sections of the Reinhart book cited above: Ceramic Powders and Processing, pp. 41122; Forming and Predensification, and Nontraditional Densification Processes, pp. 123241; Firing/Sintering: Densification, pp. 242312; and Final Shaping and Surface Finishing, pp. 313376. Thomas O. Mason