| 摘要 |
PROBLEM TO BE SOLVED: To improve strength characteristics of a translucent alumina sintered compact, above all to develop a translucent alumina sintered compact having improved strengths without compromising the translucency even in an unprocessed state of having simply been sintered.SOLUTION: The present inventors have discovered through investigations of strength improvements of alumina sintered compacts that the strength characteristic of an alumina sintered compact can be improved by 1.5 times in a case where the surface portion thereof consists of alumina or alumina complex oxide, where the average crystal grain diameter of this portion is 0.5 μm or less, and where its average crystal grain diameter is no larger than 1/2 of that of the sintered compact interior. It has been discovered that a high-strength translucent alumina sintered compact can be obtained by adding, to the alumina surface, the oxide of any of the metals of Si, Mg, and Y and by firing the resulting structure at a high temperature under a high pressure by using hot isostatic pressing (HIP). |
