| 摘要 |
<p>A process for producing high density SiC sintered bodies by primarily firing and then hot isostatic pressing is disclosed. The process comprises the steps of formulating a powder consisting essentially of 90.0 to 99.8% by weight of the SiC powder, boron or a boron-containing compound in an amount of 0.1 to 5.0% by weight when calculated as boron, and carbon or a carbon-producing organic compound in an amount of 0.1 to 5.0% by weight when calculated as carbon, and optionally up to 5 parts by weight of MgO per 100 parts of SiC, B and C and shaping the formulated powder, firing the shaped bodies in a temperature range from 1,900 to 2,300 DEG C in vacuum or in an inert gas atmosphere, and then hot isostatically pressing the fired bodies in a temperature range from 1,800 to 2,200 DEG C under a pressure of not less than 100 atms in an inert gas atmosphere. The SiC powder is an SiC mixed powder consisting essentially of 95.0 to 99.9% by weight of a first SiC powder composed of at least one kind of 3C and 2H polytypes and a second SiC powder composed of at least one kind of 6H, 4H and 15R polytypes and having an average grain diameter being less than twice that of the first SiC powder.</p> |
