LIGHT-PERMEABLE CERAMIC MATERIAL AND METHOD OF MANUFACTURING THE SAME

摘要

A light-permeable ceramic material disclosed in the specification is formed out of a plurality of oxides with negative standard Gibbs energy of formation ( DELTA Gf DEG ), whose absolute values are larger than 1581.9 KJ/mol. The ceramic is obtained by hot isostatic pressing at a high temperature and a high gas pressure. A light-permeable ceramic material of Al2O3/La2O3 is not a solid solution of Al2O3 and La2O3, but a composite in which La2O3 particles are interposed among Al2O3 particles. In this composite, the size of La2O3 is 1/3 - 1/30 of that of Al2O3 particles, and a longer axis of the largest particle of Al2O3 not more than 30 mu m, a shorter axis of the same being not more than 20 mu m, a longer axis of the largest particle of La2O3 being not more than 10 mu m, a shorter axis of the same being not more than 5 mu m. Impurities are removed from a green compact, by a treatment using a chelating agent prior to the sintering thereof, whereby the characteristics of the light-permeable ceramic material can be improved.