LAUSR

ABSTRACT To improve the ablation resistance of C/C composites under oxyacetylene flame, SiC, TaC and HfC coatings were fabricated on composites surface. Ablation properties of coatings were detected and the ablation mechanism was discussed in the paper as well. The centre region of SiC and TaC coatings has failed during ablation and exhibited high ablative rates; it attributed to so high ablation temperature, which was much higher melting point of their oxides (Ta2O5 and SiO2). HfC coating exhibited lowest ablative rates. The reason is that the ablation temperature was just between sinter point and melting temperature of HfO2, the oxides could behave as the thermal barrier coating during ablation and provide efficient protection for C/C composites. It can be indicated that the carbide coating provides best ablation protection between the Tammann temperature and melting point of their oxides.