1 - Properties of Ceramics

Abstract

Although ceramic materials for technical applications have been known for more than two hundred years, specially designed synthetic ceramics—unlike materials of traditional composition, microstructure, and properties—have been developed since approximately 1970. Advanced ceramics require a fabrication route starting from chemically well-defined, fine, highly purified, and artificial raw materials. These materials are created for distinct applications in which other conventional materials like metals or polymers have failed. Due to the large variety of chemical, electrical, biological, and mechanical properties that ceramics currently exhibit, there is almost no social or industrial application without ceramics. In the electronic and manufacturing industries, as well as in technologies that require materials sustaining extremely high temperatures and corrosive environments, high-tech ceramics play the role of key materials; novel technologies, processes, and machines are finally made possible only by means of specially tailored ceramics. Surprisingly, this development was initiated by metal scientists or—more precisely—by powder metallurgists rather than by traditional ceramists. The reason for this is that the manufacturing route used for the production of metallic parts by powder molding and compaction followed by subsequent consolidation by a heat treatment (sintering), was investigated fundamentally since the turn of the century for steel, refractory metals—and since 1920—for hard metals, which could not be cast or molded otherwise.