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. NIC and PIC show a double-layers configuration of discrete M3O4 grains and a uniform Cr2O3 layer is formed on all Cr coatings in water corrosion. Subsequent NIO and PIO show a dense Cr2O3 layer is formed in air oxidation. Results indicate the corrosion and oxidation are accelerated by irradiation-induced cavities for the arc-ion plated Cr coating, since the thickness of the formed oxide layer on irradiated coatings are larger than the one on unirradiated coatings. Importantly, morphologies of the PIC surface and the PIO cross sections is proved be related to the coating (110) 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.