Irradiation-accelerated corrosion/oxidation of the Cr coating prepared by arc-ion plating

With consideration of the normal working condition and a loss-of-coolant accident (LOCA) in a fission reactor, non-irradiation corrosion/oxidation (NIC/O) and post-irradiation corrosion/oxidation (PIC/O) for the arc-ion plated Cr coating were performed in this work. In NIC and PIC, a double-layers configuration of discrete M3O4 grains and a uniform Cr2O3 layer was formed on all Cr coatings in water corrosion. In subsequent NIO and PIO, a dense Cr2O3 layer was formed in air oxidation. These results indicate that the corrosion and oxidation were accelerated by irradiation-induced cavities for the arc-ion plated Cr coating, since the thickness of the formed oxide layer on irradiated coatings was larger than the one on unirradiated coatings. Importantly, morphologies of the PIC surface and the PIO cross sections are proved to be related to the coating (1 1 0) crystallinity measured by XRD. In mechanism, the effect of the irradiation-induced-cavity size on PIC and PIO is as important as the crystallinity. In methodology, validity of cavities in PIO is confirmed below 1000 °C.