Microstructure and Ablation Properties of the Pierced C/C-SiC Composites Prepared by Reactive Melt Infiltration

The C/C-SiC composites were prepared by chemical vapor infiltration (CVI) combined with polymer infiltration carbonization (PIC) and reactive melt infiltration (RMI) using pierced non-woven carbon fiber felt preform. The microstructure and ablation properties were investigated. The results show that non-woven carbon fiber cloth and pierced carbon fiber bundle are filled with carbon matrix prepared by CVI and PIC to form dense C/C microstructure. SiC matrix is mainly located in the felt after RMI process and the content is 37.3wt%. SiC-rich layer is formed on the surface of the composites. When the ablation distance is 20 mm and the flow ratio of oxygen and acetylene is 1:2, the ablation rates on X-Y and Z directions of the composites are 0.8×10-4 and 3.6×10-4 mm/s, respectively. The excellent ablation performance could be owing to the passive oxidation of SiC-rich layer on the surface. With the ablation distance decreasing from 20 mm to 10 mm, the ablation rate of the composites changes slowly and then increases rapidly, because of the active oxidation ablation of the composites. © 2021, Science Press. All right reserved.