Rearrangement of Oxide Scale on Ni-11Fe-10Cu-6Al Pre-Oxidized at 950 °C during Anodic Polarization in Molten Carbonate

Abstract

The effect of anodic polarization in molten Na2CO3-K2CO3 at 750 °C was investigated on the structure of oxide scale formed by pre-oxidation of Ni-11Fe-10Cu-6Al alloy at 950 °C in air. The pre-formed oxide scale evolves and rearranges under anodic polarization related to melt corrosion and non-uniformly distributed electric field. Both of pre-oxidized and as-rearranged electrodes can serve as inert anodes with oxygen evolution. Anodic polarization exhibits a negative rearrangement-destructivity effect for the pre-formed oxide scale with corrosion protection of the rearranged oxide scale decreasing. The structure rearrangement of pre-formed oxide scale is also discussed during anodic polarization in the melt.