EFFECT OF ANODIC POLARIZATION ON LAYER-GROWTH OF Fe-Ni-Cr ANODES IN CRYOLITE-ALUMINA MELTS

摘要

High-temperature corrosion behaviors of Fe-Ni-Cr alloy as inert anodes for aluminum electrolysis have been studied. The effect of anodic overpotential on layer growth of anodic surface is specially considered. The corrosion layers on the anodes tested were analyzed using XRD and SEM-EDS to provide a fundamental understanding of the layers growth at metallic anode surface. The dissolution of the scale layers on the metal anode occurred with low overpotential, while Al_xM_(3-x)O_4 spinel phase within the scale layers was found with an increased overpotential. A mixture of multiple M_yO layers existed on the anode substrate. The results may be useful for understanding and controlling the corrosion behaviors of Fe-Ni-Cr anode for potential application in aluminum electrolysis.