| 摘要 |
PROBLEM TO BE SOLVED: To obtain a silicon nitride sintered compact with a high strength surface. SOLUTION: A compact is formed from powder based on silicon nitride and contg. at least one of oxides or nitrides of Al, Y and Ta, and the compact is sintered by coating the surface of the compact with Si powder and firing the coated compact in a nitrogen-contg. atmosphere. The ratio (εB/εA) of the content εB of Al in the inner layer part of the resultant silicon nitride sintered compact in the depth range of 500-1,000μm from the surface to the content εA of Al in a part of the sintered compact close to the surface, that is, the surface layer part in the depth range of 0-500μm from the surface is regulated to <=1.5. |
