CVI沉积炭纤维束的组织结构

采用CVI工艺在常压下对单束炭纤维进行热解沉积,天然气为前驱体,N2为载气,沉积温度为1 020～1 100℃,沿纤维束轴向分布。对不同位置炭纤维束外和束内热解炭组织结构分别进行PLM表征。研究发现,束外热解炭在距离热电偶(0位置)上方40～80 mm处沉积厚度达到最大,在0～80 mm内组织结构良好,主体为高织构;束内沉积热解炭的厚度较均匀,组织结构的变化与束外一致。对气体裂解过程中的反应气体组分进行模拟并与实验对比,发现生成高织构时,热解反应中间产物中的C2H2/C6H6范围为15～35。

Texture structure of carbon fiber bundle by CVI

A single carbon fiber bundle was infiltrated by CVI at normal pressure and temperature from 1 020 ℃ to 1 100 ℃ distributed along axial direction using nature gas as precursor and nitrogen as carrier.The textures of pyrolytic carbon deposited at different position of the bundle were studied using PLM,with the aim to characterize separately the texture structure of inside and outside of fiber bundle.Results show that the thickness of pyrolytic carbon layer deposited on the fiber bundle surface reaches its maximum value at the position of 40~80 mm and high textured carbon was formed at the position of 0~80 mm.Furthermore,the thickness of pyrolytic carbon deposited inside the fiber bundle has a uniform distribution and the change of texture is similar with the outside fibers.Comparing the simulation data of mole fraction of intermediates formed at the decomposing process with the experimental results,it is indicated that high textured carbon forms when the C2H2/C6H6 ratio is within 15~35.