【摘要】 本文通过对具有不同烧结密度的热压SiC—TiC复相陶瓷在氮气氛中进行热等静压后处理,从理论上（依据热力学数据）分析了闭合SiC—TiC复相陶瓷开孔孔隙的可能性,并用实验予以证实;同时,还研究和讨论了热等静压后处理工艺对陶瓷烧结体某些物理和力学性能（密度、强度和断裂韧性）以及氧化行为的影响。实验结果表明:SiC和TiC在高的氮气压力和温度下,可以分别氮化成Si₃N₄和TiN;对于预烧结相对密度约为95％的热压SiC—TiC复相陶瓷,在200MPa氮气压力下于1850℃氮化1小时后,室温强度由345MPa提高到686MPa,断裂韧性高达7.9MPa·m^1/2,其抗氧化性能也有明显改善。更多还原

【Abstract】 Hot-pressed SiC—TiC composites with different densities were hot isostatically pressed in N₂. The possibility of that open pores can be closed was analyzed theoretically and confirmed experimentally. Moreover, the effect of post-HIPping on physical and mechanical properties such as density, strength and fracture toughness was investigated. The results showed that SiC and TiC can be transformed respectively into Si₃N₄ and TiN under high pressure N₂ and high temperature. For the SiC—TiC composites with a density of about 95％ by presintering under hot-pressing condition and after nitridation by HIPping under 200MPa in N₂ at 1850℃ for 1 h,the room-temperature strength was increased from 345 MPa to 686 MPa,the fracture toughness was up to 7.9 MPa·m^1/2and the oxidation resistance was also obviously improved.更多还原