Ablation‐resistant Ir/Re coating on C/C composites at ultra‐high temperatures

Abstract An iridium/rhenium (Ir/Re) double‐layer coating was prepared on carbon/carbon (C/C) composites by chemical vapor deposition (CVD) and electrodeposition. The morphologies and bond strengths of the coatings on the C/C substrate were examined. The ablation resistance of the Ir/Re coating was studied at 1800 °C in an oxyacetylene torch flame for 300 s. The results show that Re interlayer increases the bond strength between Ir coating and C/C substrate by over 100 %. During entire high‐temperature ablation process, Ir/Re coating keeps intact without any signs of ablation damage. Ir coating gets smoother and the grain size becomes larger after ablation, with the preferred orientation changing from to Although some voids are observed along the grain boundaries of the as‐ablated Ir coating, Ir/Re coating keeps intact on C/C composites. The study indicates that Ir/Re coating can provide good ablation resistance up to 1800 °C for C/C composites, especially for the continuous ablation applications.