Texture structure of carbon fiber bundle by CVI

A single carbon fiber bundle was infiltrated by CVI at normal pressure and temperature from 1020°C to 1 100°C 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 C ₂H ₂/C ₆H ₆ ratio is within 15~35.