Ablation mechanism of SiC coated C/C composites at 0° angle in two flame conditions under an oxyacetylene flame

•SiC coated C/C composites were ablated under oxyacetylene torch at 0° ablation angle.•Two flame conditions were used to evaluate the ablation of SiC coated C/C composites.•There was a big difference in the ablation property under two flame conditions.•The diameters reduced with the increasing of the distance to entrance after ablation.

A SiC coating was prepared on the surface of C/C composites by pack cementation and composites were ablated under an oxyacetylene flame in two flame conditions (HF1 and HF2). The gas fluxes of O2 and C2H2 in HF2 were higher than those in HF1. And the ablation angle was 0° during ablation. The ablation mechanism of composites was analysed. Results showed that SiC coated C/C composites had good ablation resistance in HF1, while SiC coating lost protection in HF2. The influence of oxyacetylene flame on the physico-chemical properties of SiC and SiO2 was the main reason for different ablation behaviours.