Preparation and ablation behavior of solid solution ceramic Ta0·2Zr0·8C–SiC matrix-modified C/C composites under high heat flux

Abstract

To further enhance the ablation resistance of C/C composites, solid solution ceramic Ta0·2Zr0·8C was used to replace traditional ultra-high-temperature ceramic carbides for matrix modification of C/C composites. The C/C–Ta0.2Zr0·8C–SiC composite was fabricated by a high-solid-loading slurry impregnation combined with the precursor infiltration and pyrolysis process. The comparative samples of C/C–ZrC–SiC and C/C–TaC–SiC were also prepared using these same technologies. The microstructure, flexural properties, and ablation performance of the composite were investigated. Results showed that the C/C–Ta0.2Zr0·8C–SiC exhibited excellent overall flexural properties. During the ablation test under an oxyacetylene flame with high heat flux, the ablation resistance of C/C–Ta0.2Zr0·8C–SiC improved with prolonged ablation time, reaching mass and linear ablation rates of 0.67 mg/s and 0.18 μm/s after 120 s of ablation. Compared to the C/C–ZrC–SiC and C/C–TaC–SiC, the mass ablation rate of the composite was reduced by 49.24% and 68.70%, and the linear ablation rate was reduced by 97.22% and 97.71%, respectively. The enhanced ablation resistance was primarily attributed to the formation of the Ta–Zr–O oxide layer, composed of TaZr2·75O8, ZrO2, and Ta2O5, on the composites surface. In the oxide layer, the Ta-rich oxides served as a binder, filling gaps in the interface. Meanwhile, the Zr-rich oxides formed the skeleton that pinned the molten liquid oxides. The combined effects of Ta-rich and Zr-rich oxides made the Ta–Zr–O oxide layer more compact and strongly bonded to the matrix.

Keywords

• Solid solution ceramic
• Matrix-modified C/C composite
• Flexural properties
• Ablation resistance