Oxidation behavior of Ni-Al coating with and without a Ni-Re diffusion barrier in dry CO_2 gas at 650℃

摘要

An electroplated interlayer of Ni-Re was prepared as a diffusion barrier to inhibit interdiffusion between Ni-Al coating and an iron alloy substrate. The oxidation behavior of the Ni-Al coating with and without the diffusion barrier was studied at 650 degrees C in dry CO2 gas for up to 660 h. The Ni-Al coating without a diffusion barrier underwent severe inner oxidation in the front of the rather thick diffusion zone (DZ) during exposure, while only slight inner oxidation was found in the Ni-Al/Ni-Re coating. The superior performance of the Ni-Al/Ni-Re coating is ascribed to its much better resistance to inner oxidation.