Effect of Nb content on microstructure, mechanical property, high-temperature corrosion and oxidation resistance of CrNb coatings for accident tolerant fuel cladding

Five CrNb coatings containing different Nb contents were deposited on zircalloy substrate by magnetron sputtering technology. The effect of Nb content on microstructure, mechanical property, high-temperature corrosion and oxidation resistance of the coatings were investigated systematically. With increasing Nb content, the surface wetting characteristics of the coating changed from hydrophilic to hydrophobic, the wear performance and the nanohardness were enhanced. The Nb addition has little effect on the corrosion resistance of the coatings. The optimal mechanical and high temperature oxidation properties were obtained for the coating with 21at% Nb content.