CORE SHELL STRUCTURED ARTICLES BASED ON ALUMINA CERAMICS AND HAVING SPINEL SURFACES

摘要

An alumina ceramic article and a method for preparing the article.The method comprises the steps of:(1) Compacting a mixture of a first concentration of particulatealuminum oxide sufficient to prevent retention of the zirconium oxide alloyparticles in the shell in a predominantly tetragonal crystal structure and a secondconcentration of particulate zirconium oxide alloy. The zirconium oxide alloy iszirconium oxide and a secondary oxide selected from the group consisting of MgO,CaO, Y2O3, Sc2O3, CeO2, and rare earth oxides having a concentration ofsecondary oxide generally of about 0.5 to about 5 mole percent Y2O3, from about0.1 to about 1 mole percent MgO, from about 0.5 to about 15 mole percent CeO2,from about 0.5 to about 7.0 mole percent Sc2O3, or from about 0.5 to about 5mole percent CaO, relative to the total of the zirconium oxide alloy. Thecompacting results in the formation of a blank.(2) Providing contact between the blank and a dopant oxide.(3) Sintering the blank in contact with the dopant oxide whereinsaid first concentration is from 50-75 weight percent of the total of the first andsecond concentrations.