Electrolysis corrosion behaviors of Fe-40Cr-5Al alloy anodes at 800℃ and 900℃

Fe-40Cr-5Al alloy anodes were prepared by vacuum induction melting for aluminum electrolysis.The electrolysis corrosion behaviors of the alloy anodes at 800℃ and 900℃ were investigated.Aluminum electrolysis tests were conducted in a cryolite-alumina low-temperature electrolyte system,at an anodic current density of 0.5A·cm^-2 for 10h.The results indicated that the corrosion rate of the alloy anodes reduced with decreasing electrolysis temperature.After electrolysis at 900℃,there was a porous corrosion layer on the anode surface,while a protective oxide scale formed after electrolysis at 800℃.The oxide scale was divided into two layers,in which the outer layer was a Fe(Al,Cr)₂O₄ spinel and the inner layer was a composite oxide consisting of Fe,Cr and O.The purity of the collected aluminium products after electrolysis at 800℃ was 98.552% and the corrosion rate of the alloy anodes was 5.51cm·a^-1.