SiC-SiO2涂层/三维碳/玻纤维编织体的制备及其抗氧化性能

Preparation of SiC-SiO2 coating/three-dimensional carbon/glass fiber braid and its oxidation-resistance properties

为获得具有抗氧化性能的三维碳/玻纤维编织体,以三维碳/玻纤维编织体为预制体,通过原位浸渍法-惰性气氛热处理在纤维表面形成SiC-SiO2涂层。利用SEM、FTIR、XRD、氧化失重等对涂层试样的组成、形貌、抗氧化性能进行表征。结果表明:通过溶胶-凝胶法成功在三维碳/玻纤维编织体的纤维表面制备出SiC-SiO2涂层,当水、正硅酸乙酯(TEOS)、乙烯基三乙氧基硅烷(VTES)和无水乙醇溶液比例为7∶7∶0.5∶11,溶胶粘度范围为3.17~4.20 mPa·s,溶胶与编织体的浸渍时间大约为35 min时,试样(碳纤维与玻璃纤维涂层厚度分别约为0.50、0.76μm)的抗氧化性能较好;涂层/三维碳/玻纤维编织体相较于初始试样的氧化转变温度提高了100℃。涂层不仅可改善编织体的抗氧化性,其力学性能比初始试样提高约65%,具备作为高温抗氧化材料的前景。

In order to obtain a three-dimensional carbon/glass fiber braid with oxidation resistance,the three-dimensional carbon/glass fiber braid was used as a prefabricated body,and a SiC-SiO2 coating was formed on the surface of the fiber by an in-situ immersion method-inert atmosphere heat treatment.The composition,morphology and oxidation resistance of the coating samples were characterized by SEM,FTIR,XRD,oxidation weight loss and other methods.The results showed that the SiC-SiO2 coating was successfully prepared on the fiber surface of the three-dimensional carbon/glass fiber braid by the sol-gel method.The sample(thickness of carbon fiber and glass fiber coatings were about 0.50 and 0.76μm respectively)had better oxidation resistance under the following conditions:the ratio of water,ethyl orthosilicate(TEOS),vinyl triethoxysilane(VTES)and absolute ethanol solution was 7∶7∶0.5∶11;the viscosity of the sol was in the range of 3.17~4.20 mPa·s;the immersion time of the sol and the braid was about 35 min.The initial oxidation transition temperature of the coating/three-dimensional carbon/glass fiber braid increased by 100℃compared with the initial temperature of the sample.The coating could not only improve the oxidation resistance of the braid,and its mechanical property was about 65%higher than that of the initial sample,which has a prospect of being used as a high temperature oxidation resistance material.