| 摘要 |
PURPOSE:To provide the title sintered compact markedly improved in toughness while maintaining high mechanical strength, with coexistence of 3C-type crystal and 6H- and/or 15R-type crystal at a specified ratio along with a specified relative density for them. CONSTITUTION:The objective sintered compact is made up of 3C-, 6H-and 15-type silicon carbide crystal phases with the 3C-type crystal phase accounting for 20-80vol.% along with its relative density of >=95 %. It is preferable that the 15R-type crystal be as little as possible. If the contents of the crystal phases do not satisfy the above-mentioned values, the toughness of the present sintered compact will not be improved because of no development of residual stress in the final sintered compact enough to increase toughness. When the relative density is too low even if the contents satisfy the above-mentioned values, the decline in the breaking strength of the present sintered compact will get significant. To obtain the present sintered compact, beta-type Sic powder or 6H- type alpha-type SiC powder with 3C-type crystal 0.1-1.0mu in mean size is incorporated with, as sintering auxiliaries, carbon etc. and a boron compound such as B4C, and the resulting form of the mixture is then calcined at 1800-2200 deg.C in an inert atmosphere. |
