Rearrangement of oxide scale on Ni-11Fe-10Cu alloy under anodic polarization in molten Na2CO3-K2CO3

•Pre-oxidation of Ni-11Fe-10Cu alloy provides an effective way to prepare an inert anode in molten carbonate.•An anodic polarization could drive the rearrangement of the pre-formed oxide scale in molten carbonate.•The anodic polarization could repair the defects of the pre-formed oxide scale.•A repair-enhancement effect of a pre-formed oxide scale improves the corrosion resistance of the nickel alloy.