Anti-oxidation and anti-corrosion properties of Al-Si metal anodes

Al-Si metal anode was fabricated by cold-press sintering with Al and Si as embedded powder in argon atmosphere. The anti-oxidation in the air and anti-corrosion in molten cryolite properties of Al-Si metal anode at high temperature were examined. The experimental results showed that the oxidation kinetics curve obeyed the parabolic law. The corrosion behavior Al-Si metal anode was studied in electrolysis test. The electrolyte consisted of Na3AlF6(90 wt%),CaF2(5 wt%) and Al2O3(5 wt%) which corresponded to molecular ratio of 2.4. The results indicated that the cell voltage was stable and the electric polarized corrosion rate was higher than the static corrosion rate of metal anode. SEM photographs showed an oxidation film formed in the surface of Al-Si metal anode which can obstruct the further corrosion in molten cryolite. It may be concluded that Al-Si metal anode has good combination property and can replace the carbon anode in the aluminum cell.