Silicon nitride sintered body, bearing balls, and bearings

摘要

PROBLEM TO BE SOLVED: To suppress the shedding of Fe-containing particles after securing Fe-containing particles of a silicon nitride sintered body, and to suppress a decrease in high-temperature strength of the silicon nitride sintered body. SOLUTION: A silicon nitride sintered body containing silicon nitride as a main component is a specific element group composed of β-phase silicon nitride particles and Ti, Zr, W, Mo, Ta, Nb, V, and Cr. It has one or more specific elements selected from the above, Fe-containing particles containing Fe, and a grain boundary phase containing at least one rare earth element, Al, Si, and O, and is silicon nitride baked. When observing the cross section of the body, the area occupied by the Fe-containing particles is 5% or less of the total, the maximum particle size of the Fe-containing particles is 5 μm or less, the Fe is 2000 ppm or more and 7000 ppm or less, and Fe. When the particle size of the contained particles is R and the ratio of the Fe content to the total content of Fe and the specific element in the Fe-containing particles is X, 0