Zr2Cu封填改性对PIP制备的C/C-SiC-ZrC复合材料微观结构和力学及烧蚀性能的影响

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

摘要:

为了改善聚合物浸渍裂解法（PIP）制备的C/C-SiC-ZrC复合材料的致密度和性能，以Zr₂Cu为填料，采用低温反应熔体浸渍工艺（RMI）对复合材料进行封孔，研究了Zr₂Cu 封填后复合材料的微观结构、力学性能和烧蚀性能。结果表明：在Zr₂Cu浸渍过程中，熔体有效地填充了复合材料的大孔隙，并且由于部分锆与碳发生化学反应，Zr₂Cu转化为ZrCu。材料的密度从1.91 g/cm³增加至2.24 g/cm³，孔隙率降低了27.35%。此外，封填后的C/C-SiC-ZrC复合材料的抗弯曲强度从122.78±8.09 MPa提高至135.53±5.40 MPa，等离子体烧蚀20 s后，与PIP C/C-SiC-ZrC相比，表现出更优越的耐烧蚀性，其质量烧蚀率和线性烧蚀率分别为2.77×10^-3 g/s和2.60×10^-3 mm/s。低熔点含铜相的“自蒸发”效应吸收了等离子火焰的热量，进一步降低了烧蚀温度，促进了SiO₂熔化层内细化ZrO₂颗粒的形成，这为Zr₂Cu封填C/C-SiC-ZrC复合材料提供了更稳定的侵蚀保护。

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.