采用化学气相浸渗法在炭纤维表面制备出不同厚度的预炭层,以ZrOCl2溶液浸渍法将锆化物引入含预炭层的预制体中,经热处理、致密化和石墨化等工艺处理,制备出一种含预炭层的ZrC-C/C复合材料。借助X射线衍射仪、扫描电镜以及能谱等手段,对材料的微观结构进行表征,采用三点弯曲实验研究材料的力学性能,并探讨预炭层厚度对材料微观结构及其力学性能的影响。结果表明,当预炭层厚度为1.5-1.7滋m时,复合材料的平均抗弯强度可达256.85 MPa,与不含预炭层试样相比,增加了67.01%；抗弯试样表现出脆性断裂模式；材料的抗烧蚀性能略有提高。
A carbon fiber preform was pre-coated with a carbon layer ( PyC) with different thicknesses by chemical vapor infiltra-tion ( CVI) , then impregnated with a ZrOCl2 ethanol solution, carbonized at 1 800℃ to form ZrC, densified by CVI to a density of 1. 75 g/cm3 and graphitized at 2 300℃ to obtain ZrC-doped C/C composites. The microstructure and composition of the composites were analyzed by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The mechanical properties were studied by three-point bend tests. The influence of the PyC layer on the microstructure, ZrC distribution and mechanical prop-erties was investigated. Results show that the average flexural strength is 256. 85 MPa when the thickness of PyC layer is 1. 5-1. 7μm, , which is a 67. 01% increase compared with the sample without the PyC layer. The cross sections of the composites after flex-ural failure show a brittle-fracture mode. The ablation resistance of the composites was slightly improved as a result of the PyC lay-er.
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