Microstructure and ablation behavior of SiMo/graphite composites with excellent short-time ablation resistance

Abstract Si-Mo alloy was infiltrated into porous graphite to develop a short-term low-ablative SiMo/graphite composite material. 19.4 vol.% residual Si was retained in the composites and significantly improved the short-term (less than 60 s) ablation resistance without sacrificing long-term (∼180 s) ablation resistance. The excellent short-term low-ablative performance is ascribed to the melt and evaporation of Si, which reduces the rate of temperature rise and supplies the consumption of SiO2 in the ablation surface. With the progress of ablation time, the ablation surface forms a SiO2-MoSi2 double layer, which acts as a barrier between the oxyacetylene flame and the ablation surface.