Fu Qiangang

TaSi2 Oxidation Protective Coating for SiC Coated Carbon/Carbon Composites

Abstract In order to improve the oxidation protective property of carbon/carbon composites at high temperature, TaSi 2 coating was prepared on the surface of SiC coated carbon/carbon composites by pack cementation technique. The crystal structure and morphology of the as-obtained coating was analyzed by XRD and SEM with EDS. The isothermal oxidation test was carried out in air at 1773 K. The results show that the as-prepared coating is composed of SiC, Si and TaSi 2 . The multilayer coating is about 200 μm in thickness, and there are no cracks in it. The results of EDS indicate that TaSi 2 can effectively fill the holes of SiC coating. There is no visible interface between the TaSi 2 outer coating and the SiC inner coating. The isothermal oxidation curve of the TaSi 2 /SiC coated carbon/carbon composites reveals that the coating can effectively protect carbon/carbon composites for 233 h at 1773 K.

聚合物浸渍裂解法制备C/C-ZrC-SiC-ZrB 2 复合材料及其性能研究

以有机ZrC、ZrB 2 前驱体和聚碳硅烷的混合溶液为浸渍前驱体, 利用聚合物浸渍裂解法(PIP)制备了C/C-ZrC-SiC-ZrB 2 复合材料, 并对材料的微观形貌、弯曲和烧蚀性能进行了研究。研究结果表明: 利用该方法可制备出陶瓷相填充充分且分布均匀的C/C-ZrC-SiC-ZrB 2 复合材料。材料的弯曲强度为126.31 MPa, 断面有大量的纤维束拔出, 表现出良好的假塑性断裂模式。经过120 s氧–乙炔烧蚀, 材料无明显烧蚀, 其线烧蚀率和质量烧蚀率分别为–2.50×10 -4 mm/s和–1.33×10 -4 g/s。在材料表面不同区域形成不同的保护层, 不仅能够降低氧气和热流向材料内部扩散, 还具有弥补缺陷的作用, 使材料表现出优异的抗烧蚀性能。C/C-ZrC-SiC-ZrB2 composites were prepared by precursor infiltration and pyrolysis (PIP) process using a mixture solution of organic ZrC, ZrB2 precursor and polycarbosilane as precursor. Microstructure, flexural prop- erty and ablation behavior of the composites were studied. The results show that the composites produced by PIP have a homogeneity distribution of ceramic phase. The flexural strength of the composites is 126.31 MPa. There are a large number of carbon fiber bundles pulled-out, and the composites exhibit a pseudo-plastic fracture behavior. After ablated for 120 s by oxyacetylene flame, the composites show no significant ablation, and their linear and mass ablation rates are -2.50×10 -4 mm/s and -1.33×10 -4 g/s, respectively. Different kinds of protective coatings