| 摘要 |
PURPOSE:To obtain a sintered material composed of beta-sialon crystal phase and a grain boundary phase containing lutetium, etc., and having improved bending strength from room temperature to high temperature and thermal shock resistance by baking a formed material containing silicon nitride as a main component and a specific amount of an assistant at a prescribed temperature. CONSTITUTION:A main component consisting of powdery silicon nitride is mixed with an assistant component consisting of the group 3a element oxide including lutetium oxide, silicon oxide and aluminum oxide or their compounds to obtain a mixture containing 0.1-10mol% of the group 3a elements in total and 1.2-8.4mol% of aluminum oxide based on the sum of the main component oxide and the aluminum oxide. The mixture is baked in a non-oxidizing atmosphere at 1600-1900 deg.C to obtain a sintered material composed of a beta-sialon crystal phase and a grain boundary phase containing group 3 elements including lutetium in combination with silicon, aluminum, oxygen and nitrogen and having a thermal conductivity of >=15 w/m.K at room temperature. |
