超高温复相陶瓷基复合材料烧蚀行为研究

Ablation Behavior of Ultra-high Temperature Composite Ceramic Matrix Composites

采用前驱体浸渍热解(PIP)工艺制备了ZrC-SiC、ZrB_(2)-ZrC-SiC和HfB_(2)-HfC-SiC复相陶瓷基复合材料,复合材料中的超高温陶瓷相均呈现出亚微米/纳米均匀弥散分布的特征,对比研究了上述材料在大气等离子和高温电弧风洞考核环境中的超高温烧蚀行为。研究结果表明,超高温复相陶瓷基复合材料相比传统的未改性SiC基复合材料,烧蚀后复合材料表面原位生成了固液两相致密氧化膜,两相协同作用实现了抗冲蚀和抗氧化的效果,对液相SiO_(2)的流失起到了阻碍作用,提升了材料的超高温烧蚀性能。在此基础上,提出了设计超高温复相陶瓷基复合材料应考虑的因素。上述研究结果对陶瓷基复合材料在超高温有限寿命领域的应用具有一定的指导意义。

Ultra-high temperature composite ceramic matrix composites ZrC-SiC,ZrB_(2)-ZrC-SiC and HfB;-HfC-SiC were fabricated by precursor infiltration and pyrolysis method.The ultra-high temperature ceramic phases in the materials were characterized by submicron/nanometer uniform dispersion distribution.Ablation behaviors of ZrC-SiC,ZrB_(2)-ZrC-SiC and HfB_(2)-HfC-SiC matrix composites under atmospheric plasma and on-ground arc-jet wind tunnel were investigated comparatively.The main factors that affect design for ultra-high temperature composite ceramic matrix composites were summarized.The result shows that,compared with traditional SiC-based composites,ultra-high temperature composite ceramic matrix composites have a solid-liquid two-phase dense oxide film formed in situ on the surface of the composites after ablation.Synergistic effect of the two phases has achieved effects of erosion resistance and oxidation resistance,which plays a very important role in hindering the loss of liquid SiO_(2) and greatly improves the ultra-high temperature ablation performance of the materials.On this basis,the important factors that should be considered in the matrix design of ultra-high temperature composite ceramic matrix composites are obtained.The above results have instructional significance for the ultra-high temperature and the limited life application of ceramic matrix composites.