三维石英纤维增强氮化物基复合材料的烧蚀性能及显微结构

Ablation Performance and Microstructure of Three-dimensional Silica Fibers Reinforced Nitride Composites

采用先驱体转化法制备了三维石英纤维增强氮化物基复合材料(3D SiO2f/Si3N4-BN),用等离子射流烧蚀方法研究了复合材料的烧蚀性能,运用扫描电镜及能谱仪对烧蚀表面微观形貌进行了观察和分析。结果表明氮化物基复合材料在高压高热流等离子体烧蚀下线烧蚀率为0.91mm/s,石英纤维熔融并被吹除带走了大量的热量,熔融层抑制了基体的机械剥蚀。基体由于强度高、升华温度高,延缓了熔融层的吹除,表明氮化物基复合材料是一种良好的耐高温烧蚀透波材料。

Three-dimensional silica fibers reinforced nitride matrix composites（3D SiO2f/Si3N4-BN） were prepared through repeated infiltration and pyrolysis.The ablation performance of the composites was evaluated by arc jet.The ablation surface and microstructures were studied by scanning electron microscope（SEM） and Energy dispersive spectroscopy（EDS）.The results show that the 3D SiO2f/Si3N4-BN composites have a low linear ablation rate of 0.91mm/s under high pressure and heat flux.Silica fibers fused and more heat was absorbed before the fused layer was swept off and the matrix eroding velocity reduced for the protective melt layer.On the other hand,the fused layer was prevented from eroding from the ablation surface as a result of the matrix with high mechanical property and sublimation temperature.The nitride composite is a high-temperature ablation resistance material for its low recession rate under high thermal load.