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

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 degrees 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 (311) to (220). 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 degrees C for C/C composites, especially for the continuous ablation applications.

Automated summary

An iridium/rhenium (Ir/Re) double-layer coating was prepared on carbon/carbon (C/C) composites, and its morphologies, bond strengths, and ablation resistance were studied. The results demonstrate that the rhenium interlayer significantly enhances the bond strength between the iridium coating and C/C substrate, and the Ir/Re coating exhibits excellent ablation resistance throughout the high-temperature ablation process.