Microstructure and ablation behaviour of C/C-SiC-ZrC-Cu composites prepared by reactive melt infiltration

To satisfy the requirements for the new generation solid rocket motors on high ablation-resistant throat materials, an idea that merges passive and active thermal protection together was applied to modify carbon/carbon composites. In this study, SiC and ZrC were used as passive thermal protection materials along with the active thermal protection material Cu to modify C/C composites. C/C-SiC-ZrC-Cu composites were prepared by twostep reactive melt infiltration, which involved the infiltration of Si/Zr followed by Cu/Ti. The Cu content of the C/C-SiC-ZrC composites was controlled by controlling the open porosity of the porous C/C-SiC-ZrC composites. Microstructure, composition and ablation resistance of the C/C-SiC-ZrC-Cu composites were investigated. The results showed that the composites with high Cu content and density exhibited excellent short-term ablation resistance under the 42 kW plasma flame, with a negative linear ablation rate after 20 s of ablation. The active heat dissipation of Cu during the ablation process results in a significant reduction of the thermal response temperature on the composite surface. Moreover, the generated Si-Ti-Zr-O layer could form an effective barrier to protect the matrix.