Ablation behaviour of C/C–ZrC composites in a solid rocket motor environment

Ablation of C/C–ZrC composites in a solid rocket motor environment was investigated. The chemical compositions of the combustion gases were calculated using the principle of free energy minimisation. The chemical thermodynamics of the products of the reactions between the combustion gases and ZrC were studied using the FactSage software. The results show that H₂O, CO₂, and OH are the main oxidising species that consume ZrC/carbon, and the oxidation of ZrC reduces carbon consumption. In addition, melting and evaporation of ZrO₂ absorb heat from the combustion gases, relieving the erosive attack on carbon. The ablation of C/C–ZrC composites is controlled by both thermal chemical ablation and mechanical breakage. The cone-shaped fibres and shell-shaped, honeycomb matrix are attributed to thermal chemical ablation, whereas the carbon fragments result from mechanical breakage.