掺加SiC片晶对反应烧结SiC性能的影响

Effect of SiC Platelets Incorporation on Microstructure and Mechanical Properties of Reaction Bonded Silicon Carbide

以液Si浸渗SiC片晶和C的坯体制备了SiC片晶增韧反应烧结SiC陶瓷材料,讨论了SiC片晶的掺加分数及烧结温度对材料显微结构和力学性能的影响,并比较了所得材料与传统反应烧结材料的力学性能。结果表明,当烧结温度较低时,SiC片晶在烧结体中仍以片晶的形态存在;而当烧结温度提高到1 800℃后,SiC片晶明显向SiC颗粒转变。与传统材料相比,掺加质量分数为40%SiC片晶制备的材料,材料抗折强度由300 MPa左右提高到587 MPa,断裂韧性由3.5MPa.m1/2提高到4.6 MPa.m1/2。

SiC platelets/C preform was infiltrated with liquid silicon to prepare reaction bonded silicon carbide（RBSC） materials. The effect of SiC platelets incorporation in the raw material on the microstructure and the properties of the sintered material were investigated. It was found that SiC platelets existed in the material sintered under low temperature（ 1 500℃）, whereas they obviously transfered to SiC particles while the sintered temperature were higher up to 1 800 ℃. Compared with the traditional RBSC ceramics, the prepared materials showed rather higher mechanical properties; when SiC platelets weight fraction in the raw material was 40% , bending strength and fracture toughness of the obtained samples were 587 MPa and 4.6 MPa· m^1/2 while the value of the traditional materials were about 300 MPa and 3.5 MPa·m^1/2 respectively.