Corrosion behavior of irradiated FeCrAlY coatings in oxygen-deficient and flowing Lead-bismuth Eutectic

In this study, Fe15Cr11Al0.5Y coatings were deposited onto the ferritic/martensitic (F/M) steel substrate by magnetron sputtering and then irradiated using 6 MeV Au 2+ at room temperature (RT). The microstructure and Lead-bismuth Eutectic (LBE) resistance of irradiated coatings under oxygen-deficient and flowing LBE were investigated. Irradiation induced the growth of coating grains, but no phase transformation or elemental segregation occurred. Progressive irradiation hardening correlates with dislocation density escalation. Irradiation leads to grain growth and a rougher surface, which accelerates the corrosion rate of the coating, but retains the three-layer oxide structure (FeCr 2 O 4 /Fe(Cr,Al) 2 O 4 /κ-Al 2 O 3 ). Moreover, the irradiated coating exhibits pronounced inward growth of κ-Al 2 O 3 along grain boundaries. The reason might be that the diffusion enhancement of elements through the defect pathway exceeds the inhibitory effect of Y, promoting the outward transport of Fe/Cr/Al and the dissolution of Al.