Formation law of dense NiFe2O4-NiAl2O4-FeAl2O4 ceramic layer on surface of NiFe2O4 based ceramic inert anode for aluminium electrolysis

摘要

To form a dense ceramic spinel layer on the surface of NiFe2O4 based cermet inert anode is one of the important ways to improve the corrosion resistance to high temperature molten salt electrolyte at present. The author examined the formation law of dense NiFe2O4-NiAl2O4-FeAl2O4 ceramic layer on the surface of NiFe2O4 based ceramic inert anode, and the experimental results show that when the alumina concentration is.3% the dense NiFe2O4-NiAl2O4-FeAl2O4 ceramic layer can always form on the surface of NiFe2O4 ceramic, NiFe2O4-10NiO composite ceramic and NiFe2O4-10NiO-15(Cu-20Ni) cermet inert anode after electrolysis for 10 h. Moreover, the atomic ratio of Fe/Ni from the anode surface to the interior is increasing, which indicates that during the dense ceraminc layer formation prior corrosion of the Fe element exists.