Influence of the iron content in Cu-Ni based inert anodes on their corrosion resistance for aluminium electrolysis

摘要

Mechanically alloyed (Cu_(3.25)Ni_(100-x)Fe_x materials (x = 0, 15 and 30 wt.%) were evaluated as inert anodes for aluminium electrolysis in KF-AlF_3 (700 ℃) electrolyte. For x = 0, the cell voltage was unstable and high (5-6 V) due to the formation of an insulting NiF* layer at the metal-oxide interface. For x = 15 and 30, the formation of a Cu_2O-rich external scale with a protective NiFe_2O_4-rich intermediate layer was favoured, resulting in a lower (~4 V) and more stable cell voltage. The purity of the produced Al was 98.96, 99.31 and 99.20 wt.% for x = 0, 15 and 30, respectively.