反应热压烧结制备ZrB2-SiC复合陶瓷的高温抗氧化性能研究

摘要

ZrB2-SiC ceramic matrix composites were prepared by reactive hot pressing at 1850℃ under 20 MPa with silicon and activated carbon as additives. The ceramic composites were exposed to 1500℃ oxidation for the research on the effect of additive content on the oxidation resistance of the samples. Phase composition and microstructure of the composites before and after oxidation were analyzed by XRD and SEM, whereafter, the antioxidation mechanism was studied. The results indicate that a porous ZrO2 scale was formed on the surface of monolithic ZrB2 sample, resulting in a poor oxidation resistance. The formation of a SiO2-rich glassy layer occurred on the sample surface during the oxidation process for sample enclosing SiC, leading to an increase in the oxidation resistance.%以硅和活性碳为添加剂，在1850℃、20 MPa条件下，利用反应热压烧结工艺制备出了ZrB2-SiC陶瓷基复合材料。复合材料在1500℃下进行高温氧化处理，研究了添加剂含量对ZrB2陶瓷抗氧化性能的影响。借助X射线衍射和扫描电镜分析了复合材料氧化前后物相组成和微观结构的变化规律，并对复合材料的抗氧化机理进行了探讨。研究结果表明：纯ZrB2陶瓷在氧化过程中形成多孔ZrO2层，其抗氧化性较差，而含SiC的复合陶瓷在氧化过程中，样品表面形成致密的富SiO2玻璃层，能显著提高复合材料的抗氧化性。