ABRASION-RESISTANT MEMBER MADE FROM SILICON NITRIDE, AND METHOD FOR PRODUCING SILICON NITRIDE SINTERED BODY

摘要

An abrasion-resistant member equipped with a silicon nitride sintered body, wherein the silicon nitride sintered body contains β-Si₃N₄ crystal particles as the main component and also contains a rare earth element in an amount of 2 to 4 mass% in terms of oxide content, Al in an amount of 2 to 6 mass% in terms of oxide content and Hf in an amount of 0.1 to 5 mass% in terms of oxide content. The abrasion-resistant member is characterized in that the silicon nitride sintered body contains crystals of a (rare earth)-Hf-O-type compound, wherein the area ratio of the crystals of the (rare earth)-Hf-O-type compound per unit surface area, i.e., 30 μm × 30 μm, of a grain boundary phase in an arbitrary cross section is 5 to 50%, and the variation in the area ratio of the crystals of the (rare earth)-Hf-O-type compound per the above-mentioned unit surface area is within 10%. This constitution enables the provision of an abrasion-resistant member which comprises a silicon nitride sintered body having excellent abrasion resistance and good processability.