窒化珪素質焼結体、ベアリングボール、およびベアリング

Japanese Patent JP7267151

B2

To inhibit the breakoff of Fe-containing particles by securing those particles of a silicon nitride sintered compact to restrain deterioration in the high-temperature strength of the sintered compact.SOLUTION: A silicon nitride sintered compact including silicon nitride as a main component includes: the β phase type silicon nitride particles; Fe-containing particles containing Fe and at least one specified element selected from the specified element group consisting of Ti, Zr, W, Mo, Ta, Nb, V and Cr; and a grain boundary phase including at least one rare-earth element, Al, Si and O. When observing a cross section of the silicon nitride sintered compact, the area occupied by the Fe-containing particle is 5% or less of total area, and the maximum particle size of the above particle is 5 μm or less. The sintered compact includes Fe of 2,000 ppm or more but 7,000 ppm or less and satisfies the expression of 0