| 摘要 |
PURPOSE: To obtain a high-density uniform silicon nitride sintered compact with low surface porosity having a high mechanical strength. CONSTITUTION: This sintered compact is obtained by coating the surface of a silicon nitride-predominant sintered compact with a mixed powder in which silicon nitride powder, boron nitride powder and a sintering auxiliary component- contg. powder are dispersed and sintering the mixed powder. The mixed powder is composed of oxide(s), nitride(s) or oxynitride(s) each containing at least one element selected from among Si, Al, Y, Yb, Zr, Mg, Hf, La and B. Besides, this sintered compact has the following characteristics, that is, the size of pores contained within the range from the sintered surface to a depth of 200μm is 5-50μm, and the pore area accounts for <=15% of a surface area of 100μm<2> .
|
