Effects of Zr2Cu Packing Modification on Microstructure and Mechanical and Ablation Properties of PIP-Prepared C/C-SiC-ZrC Composites

Abstract:

To improve the compactness and properties of C/C-SiC-ZrC composites produced by precursor infiltration and pyrolysis (PIP) method, the low-temperature reactive melt infiltration (RMI) process was used to seal the composites using Zr₂Cu as the filler. The microstructure, mechanical properties, and ablation properties of the Zr₂Cu packed composites were analyzed. Results show that during Zr₂Cu impregnation, the melt efficiently fills the large pores of the composites and is converted to ZrCu due to a partial reaction of zirconium with carbon. This results in an increase in composite density from 1.91 g/cm³ to 2.24 g/cm³ and a reduction in open porosity by 27.35%. Additionally, the flexural strength of Zr₂Cu packed C/C-SiC-ZrC composites is improved from 122.78±8.09 MPa to 135.53±5.40 MPa. After plasma ablation for 20 s, the modified composites demonstrate superior ablative resistance compared to PIP C/C-SiC-ZrC, with mass ablation and linear ablation rates of 2.77×10^-3 g/s and 2.60×10^-3 mm/s, respectively. The “self-transpiration” effect of the low-melting point copper-containing phase absorbs the heat of the plasma flame, further reducing the ablation temperature and promoting the formation of refined ZrO₂ particles within the SiO₂ melting layer. This provides more stable erosion protection for Zr₂Cu packed C/C-SiC-ZrC composites.