Influence of SiC additive on the ablation behavior of C/C composites modified by ZrB2–ZrC particles under oxyacetylene torch

To determine the effect of SiC additive on the ablation behavior of carbon/carbon composites modified by ZrB2–ZrC particles (C/C–Z), C/C–Z and C/C–Z with SiC additive (C/C–Z–SiC) were ablated by oxyacetylene torch for different times up to 240 s. Results showed the improved ablation property of C/C–Z–SiC in comparison with C/C–Z during the initial 120 s but depletion of the improvement with the ablation further proceeding. Meanwhile, the recorded surface temperature of C/C–Z–SiC was lower than that of C/C–Z under the same ablation condition during the initial 160 s after which they tended to be the same. The ablated surface center morphology of C/C–Z–SiC implied that a SiO2 rich layer was formed beneath the chalked ZrO2 outer layer within 120 s ablation while the SiO2 rich layer was almost depleted beyond 240 s. The formation and depletion of SiO2 rich layer from oxidation of SiC additive dominated the distinct ablation behaviors of C/C–Z–SiC and C/C–Z.