FIGURE 1 Cracks formed at the boundary of an MgO bicrystal, caused by piling up of edge dislocations. From Westwood.⁷

systems, SiC as a candidate material for the leading edge of wings on hypersonic aircraft, the dielectric behavior of zirconates and simple niobates, and the use of garnets and ferrites for computer memories.⁸ However, most papers were still concerned with refractories for furnace walls and with enamels and whitewares—the mainstays of the ceramics industry at that time. Parker⁹ succinctly summed up the state of affairs 25 years ago when he said in his closing remarks to the North Carolina State meeting, “The most important thing we have learned in this conference is how little we really know about complex ceramic materials…. Each speaker, talking for something like half an hour, or even less, was running out of things to say by the time he was finished.”

The years 1960–1980 have served as the long period of slowly increasing investment in research and development and technical advances that often precedes the S-curve development of a new industry. We are now entering the initial growth phase of the advanced ceramics industry, in which scientific understanding and developments are exploited in diverse areas, completely new applications are appearing, and companies are beginning to compete for market share. This chapter briefly reviews some of the ways in which the