Effects of LaB6 on composition, microstructure and ablation property of the HfC-TaC-SiC doped C/C composites prepared by precursor infiltration and pyrolysis

HfC, TaC and SiC with different proportions were introduced into Cf/LaB6 preform to fabricate four kinds of UHTC doped C/C composites. Results show that LaB6 could react with HfC or TaC to establish a compact ceramic structure. After ablation for 120 s, the composites doped with LaB6-HfC-TaC-SiC possessed the best ablation property, and the ablation rates were 1.129 mg/s and 3.133 ?m/s. A layer with La2Si2O7, La2Hf2O7 and LaTaO4 is observed due to the reactions between La2O3 and other binary oxides. Further ablation was suppressed and stability of the multi-phase layer is therefore confirmed, indicating good coordination among the oxides.

Automated summary

By introducing HfC, TaC, and SiC into the Cf/LaB6 preform, four kinds of high-performance UHTC doped C/C composites were fabricated, showing excellent ablation resistance and stability. The composite doped with LaB6-HfC-TaC-SiC exhibited the best performance, with good coordination among the oxides, leading to suppressed further ablation and confirmed stability of the multi-phase layer.