Ablative property and mechanism of SiC-CuxSiy modified C/C-ZrC composites prepared by a rapid method

A rapid method was developed to fabricate C/C-ZrC-SiC-CuxSiy composites with low open porosity by precursor infiltration and pyrolysis combining with pressure assisted reactive melt infiltration. Dominant phases of ZrC and SiC with scattered CuxSiy inclusions were present in continuous infiltrated matrix, in which the dimension of submicron ZrC particles displayed gradient change. At ablation test, the heat absorbing effect of CuxSiy-phase and formation of protective ZrO2-SiO2 cover enhanced the ablative property of composites for short-time ablation, causing ablation rates of 30 s ablation reached 1.7 +/- 0.1 mu m/s and 1.3 +/- 0.1 mg/s, respectively. As ablation time extends to 60 s, the massive consumption of Si-phase damaged the integrity of surface oxide cover, but the partial melted ZrO2 improved the viscosity and self-healing ability of ZrO2-SiO2 mixture, protecting substrate from further erosion. Thus, ablation rates were increased and decreased to 3.8 +/- 0.2 mu m/s and 1.2 +/- 0.1 mg/s, respectively.