Study on C/C Composites Ablated in Plasma jet

摘要

In order to solve thermal protection problems under atmospheric reentry conditions, some tests on the earth have been done to study antiablative properties of C/C composites in thermal plasma jet. The flow fields and the parabola distribution of the plasma jet has been found. Furthermore, metals melting point method was used to survey the temperature of the plasma jet fields. Calculating the ablation ratios, spectrum analysis tested the ablation productions, scanning the ablation area, and combining the plasma characters, the ablating mechanisms of C/C composites has been found. Oxidation and nitrification are dominating factor when there is no Al_2O_3 particle in the flame, and the productions include CN, C_2, C_1, CO and little CO_2. The fibres are bare, whose shape are pyramidal in the breakpoint and netlike in the bottom. Whereas mechanical erosion is dominating factor when Al_2O_3 particle is appended in the flame, and the productions are mostly CO and CN. The boundary is neatly, and the bottom is smoothly. What's more, the ablation properties of C/C composites are little different from different angle flames.