SILICON NITRIDE SINTERED BODY, METHOD FOR PRODUCING SAME, AND ABRASION-RESISTANT MEMBER AND BEARING EACH PRODUCED USING SAME

摘要

A silicon nitride sintered body according to an embodiment contains aluminum in an amount of 2 to 10 mass% in terms of oxide content, at least one R element selected from rare earth elements in an amount of 1 to 5 mass% in terms of oxide content, and at least one M element selected from Group 4A elements, Group 5A elements and Group 6A elements in an amount of 1 to 5 mass% in terms of oxide content. The ratio of the content of aluminum to the content of the R element is 2:1 to 5:1 in terms of oxide contents, and the ratio of the content of aluminum to the content of the M element is 2:1 to 10:1 in terms of oxide contents. The silicon nitride sintered body according to the embodiment can be used as an abrasion-resistant member such as a bearing ball.