In order to improve the oxidation resistance of C/C composites, ZrO2/SiO2 coatings were prepared on the surface of C/C composites by atmospheric plasma spraying(APS), and oxyacetylene test was proceeded at 1 450, 1 700, 2 000 ℃ to evaluate the anti-ablation performance of the coating. In addition, the composition and microstructure of the agglomerated powder and coating before and after ablation treatment were detected. Results showed that atmospheric plasma spraying was a feasible method to prepare ZrO2/SiO2 coating on the C/C substrates surface. However, due to the huge difference of the melting point between ZrO2 and SiO2, the powders were hardly melting sufficiently causing 40.12% porosity of the coating, and the binding strength of the coating was 12.1 MPa. The ablation resistance of ZrO2/SiO2 composite coating was good. With the increase of temperature, the protection mechanism of ZrO2/SiO2 composite coating could be divided into two stages: in the low temperature stage, SiO2 melted and sealed to the healing effect, the density was increased, and ZrO2 gradually formed a skeleton and supported liquid SiO2. In the high temperaturestage stage, the SiO2 gradually evaporated and lost, and only ZrO2 remained in the coating and sintered, which continued to play a role of anti-oxidation ablation.
