制备工艺对热压烧结SiC/SiC复合材料结构与性能的影响

采用纳米SiC和亚微米SiC粉料作为基体形成原料,通过热压烧结技术制备了SiC/SiC 复合材料.研究了粉料颗粒、烧结温度、烧结压力对复合材料显微结构和各种性能的影响.结果显示,采用纳米碳化硅粉体可有效降低烧结温度,促进复合材料的致密化过程,在1780℃、20MPa条件下可获得性能优良的复合材料.而采用亚微米SiC粉体,复合材料的致密化过程需要较高的温度,但随着密度的增加,基体与纤维之间的作用力增强,不利于性能的提高.

Effects of Preparation Conditions on the Microstructure and Properties of Hot Pressed SiC/SiC Composites

SiC/SiC composites were prepared by hot pressing using nano-SiC and sub-micrometer SiC powders for matrix formation. The effects of preparation conditions, such as particle size, sintering temperature and sintering pressure, on the microstructural evolution and mechanical properties were characterized. The composite using nano-SiC for matrix formation could promote densification at a relatively lower temperature. At 1780℃, 20MPa, a high performance composite, N-SiC/SiC, could be obtained. While using sub-micrometer SiC for matrix formation, fiber and matrix interaction was enhanced with the increasing of eityer sintering temperature or pressure, which would disbenifit for the performances of the composite.