| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a silicon nitride sintered compact suitable for a rolling bearing member having a mechanical strength, an abrasion resistance, and a rolling life property equal to or higher than those of a conventional silicon nitride sintered compact and an excellent processability as well and its manufacturing method, where the dispersion of an aid component can be controlled so as to be homogeneous and reduce an unevenness of a grain boundary strength in case that a silicon nitride raw material powder with a low purity and a low price such as a silicon nitride powder prepared by the metal nitridation method is used for forming. <P>SOLUTION: The silicon nitride sintered compact contains a rare-earth element of ≤3 mass%, an Al element of ≤3 mass%, and an oxygen element of ≤5 mass% as a sintering aid component and the β-type formation rate of the silicon nitride is 95% or more. In the crystal structure of the silicon nitride sintered compact, the area ratio of silicon nitride acicular crystal particles with an ratio of major axis vs. minor axis of ≥2 is 50% or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
