Electrolytic Production of Aluminum Using Mechanically Alloyed Cu–Al–Ni–Fe-Based Materials as Inert Anodes

materials with varying from 0 to 20 (wt %) were prepared by mechanical alloying. For , the as-milled was made of an α-phase, whereas was formed at . Upon consolidation, a small amount of κ Ni/Fe-rich Al phase with a B2 structure is formed for and 10, whereas no new phase is formed in the other compounds. Aluminum electrolysis tests conducted at an anode current density of for 20 h in a low temperature electrolyte showed that the electrode stability and aluminum purity are strongly dependent on the alloy composition. The lowest values of cell voltage (4.1 V) and Cu contamination (0.8 wt %) were obtained for . This relatively lower contamination is due to the formation of a dense and adherent oxide scale between the outermost oxide layer and the substrate. In comparison, a hot-rolled C63000 commercially available alloy with the same composition but lower chemical/microstructural homogeneity gave a higher Cu contamination level (1.4 wt %).