Ablation behavior of three-dimensional C-f/SiC-ZrC-ZrB2 composites prepared by a joint process of sol-gel and reactive melt infiltration

Three-dimensional C-f/SiC-ZrC-ZrB2 composites were fabricated by a joint process of sol-gel and reactive melt infiltration. Ablation test of the composites was performed under air plasma. The composites showed negative recession rates at 1800-2000 degrees C, while positive recession rates above 2000 degrees C. Results revealed that dense SiO2-ZrO2-B2O3 layer formed on the sample surface prevented the ablation process extending inward the samples. At higher temperature, active oxidation of SiC and severe evaporation of oxide phase significantly impaired the integrity of the oxide layer and inevitably deteriorated the resistance of the oxide layer to the air plasma.