SiO_2涂层制备工艺对三维碳纤维编织体抗氧化性能的影响

Influence of SiO_2 Coating Preparation Process on the Oxidation Resistance of 3-D Carbon Fiber Braids

采用溶胶-浸渍法,在三维碳纤维编织体的纤维表面涂覆SiO_2涂层。实验研究了涂层制备工艺对编织体抗氧化性能的影响。结果表明,纤维经丙酮、硝酸处理后,再采用粘度为0.01～0.012(Pa·s)、分子生长模式为线性的溶胶浸渍,当涂层厚度为0.5μm左右时,浸渍试样抗氧化性能好,完全氧化失重温度为900℃,较之原始编织体提高300℃。涂层过厚或过薄,编织体抗氧化性能下降,这是由于涂层在纤维表面分布不均匀或与纤维表面结合性较差引起的。

The SiO2 coating on 3-D carbon fiber braids was prepared by the sol-dipping method. And the influence of coating preparation process on the oxidation resistance of the braids was also studied. The results show that the oxidation resistance of the dipped sample is improved 300degreesC comparing with the raw braids, when the braids are treated by nitric acid. Then it is dipped with the sol, of which the viscosity is between 0.01similar to0.012(Pa.s)and the molecule growth model is linear. The thickness of coating is about 0.5mum. The oxidation resistance of dipped samples decreases when the thickness of coating is either thicker or thinner, because the coating is coated asymmetrically or combined badly with fiber surface.