Effects of ZrC/SiC ratios on mechanical and ablation behavior of C/C–ZrC–SiC composites prepared by carbothermal reaction of hydrothermal co-deposited oxides

C/C-ZrC-SiC composites were fabricated by carbothermal reaction of hydrothermal co-deposited oxides and resulted in homogeneous microstructure. The fracture behavior passed from pseudo-plastic to brittle fracture with the increase in ZrC/SiC molar ratios. The composites with a molar ratio of ZrC/SiC≈2:1 presented outstanding ablation resistance with a mass ablation rate of 0.06 mg cm⁻² s⁻¹ and a linear ablation rate of 0.13 μm s⁻¹. The optimal ZrC/SiC molar ratio provided a suitable balance of viscosity and flowability of the oxides scale, which not only possessed enough solid ZrO₂ to endure the scouring but also had moderate liquid-phase to seal the defects and limited the oxidation.