Effect of Ion Irradiation on Corrosion Behavior of Two Medium-Entropy Alloy Coatings in Simulated PWR Primary Water

We investigated the impact of Au ion irradiation on the corrosion behavior of medium-entropy alloy coatings (MEAs), with and without Al addition, in simulated primary water of pressurized water reactors (PWRs). The results indicated the formation of double-layer oxide films on the surfaces of both types of coatings, consisting of outer oxide particles and a protective inner oxide layer. The high-fluence irradiation modified the microstructures of both coatings and accelerated their corrosion kinetics. However, the coating with a slight addition of Al demonstrated superior post-irradiation corrosion resistance owing to its enhanced lattice distortion effect within the system, inhibited atomic diffusion, and reduced impact of irradiation on its phase structure. A comprehensive discussion was carried out on the corrosion processes of the coatings, both irradiated and non-irradiated.