Ablation behaviour and mechanical performance of ZrB₂-ZrC-SiC modified carbon/carbon composites prepared by vacuum infiltration combined with reactive melt infiltration

The development of advanced aircraft relies on high performance thermal-structural materials, and carbon/carbon composites (C/C) composited with ultrahigh-temperature ceramics are ideal candidates. However, the traditional routes of compositing are either inefficient and expensive or lead to a non-uniform distribution of ceramics in the matrix. Compared with the traditional C/C-ZrC-SiC composites prepared by the reactive melt infiltration of ZrSi₂, C/C-ZrB₂-ZrC-SiC composites prepared by the vacuum infiltration of ZrB₂ combined with reactive melt infiltration have the higher content and more uniform distribution of the introduced ceramic phases. The mass and linear ablation rates of the C/C-ZrB₂-ZrC-SiC composites were respectively 68.9% and 29.7% lower than those of C/C-ZrC-SiC composites prepared by reactive melt infiltration. The ablation performance was improved because the volatilization of B₂O₃, removes some of the heat, and the more uniformly distributed ZrO₂, that helps produce a ZrO₂-SiO₂ continuous protective layer, hinders oxygen infiltration and decreases ablation.