On the mechanism of densifying unidirectional C/C composites by isothermal chemical vapor infiltration

The densification process of unidirectional carbon-carbon composite prepared by isothermal chemical vapor infiltration (ICVI) was studied experimentally. According to the two stages of pyrolytic carbon, the densification process may be divided into two stages, disperse phase and continuous phase. The densification uniformity was discussed emphatically. The effects of fiber volume fraction and penetrate pores on densification process were analyzed. The results have shown that the lower the fiber volume fraction is, relatively the faster the rate of densification is, and more obvious the effect of densification is. The existence of penetrate pores in preform can enhance capacity of mass transfer of acrylic gas and improve the effect of densification.