Effects of surface structure unit of 2D needled carbon fiber preform on the microstructure and ablation properties of C/C-ZrC-SiC composites

To investigate the effects of different structure units on the ablation properties of C/C-ZrC-SiC composites produced from 2D needled carbon fiber preforms as reinforcements, non-woven layer, short-cut fiber web and the surface of laminated layers of the composites were ablated by oxyacetylene flame respectively. Results showed that the formation ability of surface protective layer and the fiber orientation were the key factors, determining ablation properties of different structure units. Short-cut fiber web presented the best ablation resistance due to the forming of compactly integrated ZrO2 self-protection coating because of its sufficient ceramic content. However, only scattered oxide particles formed on the ablated surface of non-woven layer, which resulted in serious erosion of carbon fibers and carbon matrices, leading to the poor ablation resistance. Compared with the non-woven layer perpendicular to the flame, the anti-ablation property was even worse when it paralleled to the flame.