Corrosion Behavior of Inconel 625 Overlay and N‐Containing Nickel‐Based Overlay in Molten LiF‐NaF‐KF

To address nickel deficiency, inspired by high‐nitrogen steel, this study replaced Ni with N. Based on Inconel 625, five N‐containing nickel‐based flux‐cored wires were designed and prepared. These, along with Inconel 625 wire, were used to create overlays via MIG/MAG welding. Hot corrosion tests in LiF+NaF+KF molten salt at 600°C showed the N‐containing overlay's weight loss was at least 0.401 mg/mm 2 , significantly lower than Inconel 625's 0.483 mg/mm 2 . XRD, SEM, and EDS revealed identical corrosion products (NiCr 2 O 4 , Cr 2 O 3 , FeCr 2 O 4 , and NiO). XPS indicated the N‐containing overlay had more protective, dense Cr 2 O 3 , while Inconel 625 formed more porous NiO. Thus, the N‐containing overlay exhibits superior FLiNaK salt corrosion resistance.