| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a low-cost silicon nitride sintered compact which is excellent in mechanical properties and shows little dimensional change at baking by preventing temperature runaway by controlling an exothermic reaction in a substantially nitrogen atmosphere at nitriding of the silicon nitride sintered compact obtained through reaction sintering. <P>SOLUTION: A process for manufacturing the silicon nitride sintered compact comprises a nitriding step wherein a molded product essentially comprising a mixture of a Si powder and a silicon nitride powder and containing an oxide of a group 3a element of the periodic table is nitrided at 1,000-1,500°C to obtain a nitrided product and a baking step wherein the nitrided product is baked and compacted in a nitrogen-containing, and non-oxidizing atmosphere. Here, the atmospheric pressure inside a furnace is adjusted to 5-40 kPa until the cumulative input of nitrogen gas per 1 kg Si since the initiation of nitriding in the nitriding step reaches 0.2 Nm<SP>3</SP>, and after it exceeds 0.2 Nm<SP>3</SP>, the atmospheric pressure is adjusted to 20-120 kPa to convert Si into silicon nitride. <P>COPYRIGHT: (C)2004,JPO |
