The behavior of Cu-Ni-Ag-Al alloy used as anode for aluminum electrolysis was directly visualized in a two-compartment see-through cell during electrolysis, and its performances were tested at 850℃ in acidic electrolyte molten salts consisting of NaF-AlF3-8%NaCl-5%CaF2-4%Al203 for 40h in a laboratory cell. The results show that nascent oxygen oxidized the anodic surface to form oxide film at the beginning of electrolysis. Post electrolysis, X-ray diffraction analysis of alloy surface show oxide film on the anodic surface consist of CuO, NiO, A12O3, CuAl2O4 and NiAl2O4. However, SEM photo shows the oxide film is porous, loose and easy to fall into electrolyte and contaminate aluminum. The corrosion mechanism of metal anodes is analyzed in this paper.
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