CVD碳化硅薄膜对炭纤维表面结构和性能的影响

Effect of coating SiC film on suface structure and property of carbon fiber by CVD method

以三氯甲基硅烷(CH3SiCl3,MTS)为碳化硅源,采用化学气相沉积(CVD)的方法,在去胶炭纤维表面沉积一层碳化硅薄膜。采用SEM及N2等温吸附观察的方法,分析了薄膜处理对炭纤维表面结构的影响。结果表明:CVD碳化硅薄膜能够修复炭纤维表面的微孔和裂纹等缺陷,使纤维表面更光滑,可以改变纤维的表面结构特性,使炭纤维的BET比表面积和BJH累积孔体积降低,从而降低炭纤维表面吸附能力。采用单丝拉伸试验机进行力学分析,通过干烧对比实验发现:在CVD过程中,考虑沉积气氛对纤维损伤的影响,炭纤维在CVD碳化硅薄膜修复后,抗拉强度和弹性模量分别提高了6.7%和8.2%。

A layer of silicon carbide （SIC） thin film was coated by using trichloromethyl silane （CH3SiCl3, MTS） as the source of SiC during the chemical vapor deposition （CVD）. The effects of coating treatments on the surface structure of carbon fiber （CF） were investigated by scanning electron microscopy （SEM） and isotherm absorption. The results show that the treatments can renovate the micro-holes and cracks on CF surface, making the fiber surface more smooth, and can improve the surface structure of CF. The BET surface area（TSA） and BJH cumulative adsorption pore volume （BPV） decrease which reduces the surface absorption capability of CF. The mechanical analysis was studied using monofilament tensile testing machine and the dry combustion method , which indicates that considering the influence of sedimentary atmosphere on fiber, the tensile strength and elastic modulus increase 6.7% and 8.2%, respectively, after coating SiC film on CF during CVD.