Powder for toughened zirconia ceramics; Kokyodo kojinsei zirconia funmatsu

High-strength high-tenacity zirconias are sold as stabilizers that are added with several kinds of metal oxides. This paper introduces Y2O3 partially stabilized zirconia which is most advanced in application development among other materials. The zirconia is characterized by its capability of sintering in atmosphere, high specific gravity, high thermal expansion rate, low heat conductivity, low hardness, oxygen ion conductivity, and low Young`s modulus. The material has applications developed as ceramics that are `close to metals at normal temperatures`. It is manufactured mainly by the hydrolytic process and the neutralizing coprecipitation process. However, the hydrothermal polymerization-pyrolytic process has been developed more recently. Requirements from sinter manufacturers have been changed from the improved strength and tenacity to higher quality stability, higher workability, easier degreasing performance, more densification at low temperatures, and higher purity. Its application has been increasing in recent years for industrial cutter blades, optical connector parts, and crushed member media, with its consumption having grown to 280 tons/year in 1991. However, its use is somewhat stagnant since then. 7 refs., 2 figs.