Effects of oxygen content on the ablation/erosion behavior of 4D carbon/carbon composite material

Abstract

A self-designed oxygen-kerosene ablation system was employed to test the four-directional braided carbon/carbon (4D C/C)composite material for studying the ablation performance under different oxygen-rich conditions, that is, −5%, 0% and 5%. The morphology of post-test specimens was analyzed via a scanning electron microscope(SEM), and the ablation rates were calculated. The influence principle of oxygen content on the ablation behavior of carbon/carbon composite material was studied, and the mechanism of ablation was also analyzed. Experimental results showed that the oxygen content will mainly affect the thermo-chemical ablation. The maximum mass ablation rate was 0.161 g · s−1 when the oxygen content was 5%, while the minimum was 0.146 g · s−1 when the oxygen content was 0. Within the range, the interstice between the axial fiber bundle and matrix became larger with the increase of oxygen content. In the two-phase flow test, the effect of particle erosion on material damage was much stronger than the change of oxygen content; on the other hand, fiber bundles were broken particles to form fine particles attaching to fracture fibers, which increased the contact area of the oxidation reaction and indirect accelerated thermochemical ablation process, the number of small carbon particles attaching to the surface gradually decreased with the increased of oxygen content.