Fabrication of PyC/SiC Compound Coating on Carbon Fiber Preform and Its Effect on the Properties of Cf/Al Composite

摘要:

为改善碳纤维与熔融铝合金间的润湿性、减小界面反应程度，采用化学气相沉积（CVD）法在碳纤维预制体表面沉积制备了PyC/SiC复合涂层，利用真空吸渗挤压浸渗工艺制备了Cf/Al复合材料。研究了沉积参数对碳纤维表面涂层的影响，并通过复合材料微观组织分析及材料机械性能测试来反映涂层对Cf/Al复合材料的浸渗质量和性能的影响规律。结果表明：沉积温度对涂层沉积速率影响较大，通过选择合适的沉积温度或者沉积时间，可在碳纤维表面得到厚度均匀的PyC/SiC复合涂层。碳纤维预制体表面涂层的存在可使其与基体合金润湿性良好、界面结合强度适中，形成合适的界面结合状态，有效提高浸渗质量和复合材料性能；并且当PyC涂层、SiC涂层厚度分别为0.068、0.257 μm时，复合材料性能改善效果最佳

Abstract:

PyC/SiC compound coating was deposited on carbon fiber preform by chemical vapor deposition (CVD) process for improving the wettability and reducing the chemical reaction between molten aluminum alloy and carbon fibers. Cf/Al composites were fabricated through the extrusion directly following vacuum pressure infiltration process. Effects of coating deposition parameters on the quality of carbon fiber coating were studied, and the influences of the coating on the infiltration quality and the mechanical properties of composites were also investigated by means of the microstructural analysis and mechanical property tests. The results show that the deposition rate of the coating is mainly controlled by the deposition temperature, and the uniform thickness of PyC/SiC compound coating can be obtained by controlling the deposition temperature or deposition time. The coating on carbon fiber preform can improve the infiltration quality and mechanical properties greatly based on the suitable interface bonding strength and good wettability. The optimized PyC/SiC compound coating thicknesses are 0.068 μm (PyC coating) and 0.257 μm (SiC coating) for better improving the composite properties