The behavior of the additive Yb₂O₃ doped in the anodes during electrolysis

Investigation of the behavior of additive Yb₂O₃ in the anode during electrolysis is an important method for improving the corrosion resistance of the grain boundary to high-temperature molten salt electrolyte. The author examined the Yb content of cermets after both sintering and electrolysis and the experimental results showed that a dense layer of NiFe₂O₄-NiAl₂O₄-FeAl₂O₄ ceramic favorably formed on the surface of the anodes only if the electrolysis time was greater than 10 hours. Moreover, NiFe₂O₄, NiA₂O₄ and FeAl₂O₄ were produced and dissolved continuously as a result of the chemical and electrochemical corrosion that took place after the formation of the dense layer. As the electrolysis time was extended, Yb₂O₃ or YbFeO₃ gradually dissolved into the electrolyte and primary aluminum as an impurity substance.