Preparation and ablation performance of (ZrC/SiC)35 multilayer alternating coating with sub-micro sublayers thickness

A (ZrC/SiC) 35 multilayer alternating coating with 500∼700 nm sublayers thickness and 70 interfaces was deposited on sharp leading edge C/C composites by continuous CVD method. Its mechanical property and ablation resistance were assessed by scratch test and oxy-acetylene flame respectively and compared with ZrC monolayered coating. The (ZrC/SiC) 35 multilayer alternating coating exhibited a high bonding strength via the regulation of sub-micro alternating stress field and the inhibition of crack propagation by 70 interfaces, showing a high critical load L C3 of 22.521 N, which was higher than that of ZrC monolayered coating of 5.688 N. Furthermore, the coating revealed excellent ablation resistance evidenced by its intact oxide layer, and the mass and linear ablation rates were only 0.17 mg/s and 0.87 μm/s respectively. The layer-by-layer oxidation behavior allowed the advantages of ZrC and SiC sublayers to be fully utilized, thus maintaining the layered oxide structure. Furthermore, the total 35 layers of thin ZrO 2 layers improved the fault tolerance ability of coating in harsh ablative environments.