Wind tunnel ablation behaviors and synergistic effect of the Ir/HfC coating

An Ir/HfC composite anti-ablation coating was designed by combining the oxygen barrier property of Ir with the ablation resistance of HfC. The Ir/HfC coating was prepared on graphite and was subjected to an ablation test in a plasma wind tunnel. The results show that the Ir/HfC coating passed an ablation test of 2000∼2300°C/2000 s + 2500°C/200 s with no defects and the mass ablation rate was -2.3×10 -5 g·cm -2 ·s -1 . With combination of heat treatment experiments, it was found that the interfacial evolution of the coating released the stresses at the oxidation interface of the HfC coating while blocking the heat transfer to the Ir coating, promoting the Ir/HfC coating to exhibit excellent ablation resistance. The synergistic effect of each layer makes the Ir/HfC coating a thermal protection coating with ultra-high temperature and wide temperature range ablation resistance.