| 摘要 |
PROBLEM TO BE SOLVED: To provide a silicon nitride-based sintered compact with a higher strength, a higher toughness and a higher hardness. SOLUTION: This high-toughness silicon nitride-based sintered compact contains a Ti compound 2 such as a nitride, a carbide and a carbonitride of Ti dispersed in a matrix 1 consisting essentially of silicon nitride. An aggregated region 3 containing the Ti compound 2 densely present is scattered in the matrix 1. The Ti compound 2 especially contains a fibrous material having at least 0.1-2 μm average minor axis and 2-50 average aspect ratio in a volume of 1040 vol.% in the total amount and the aggregated region 3 is preferably present in a size of 20-200 μm. The matrix 1 consists essentially of a β-silicon nitride crystal phase and is composed of a grain boundary phase containing a group 3a element of the periodic table. At least one kind of Ni, Co, W, Mo, Mn, Cu and Fe is preferably present as an oxide, a nitride, an oxynitride or a silicide in the boundary with the Ti compound. |
