Electric conductivity and corrosion resistance of Co-Ni-xNiFe₂O₄ inert anodes

Cold isostatic press sintering is adopted to prepare Co-Ni-xNiFe₂O₄(x=5%, 10%, 15% and 20wt%) metal based inert anodes for aluminum electrolysis. The electric conductivity and corrosion resistance of electrolyte are investigated. The experimental results show that the electric conductivity of anode decreases with increasing the content of NiFe₂O₄ and temperature. The electric conductivities of 47.5Co+47.5Ni+5.0 NiFe₂O₄ and 42.5Co+42.5Ni+15.0NiFe₂O₄ are 550 S·cm^-1 and 300 S·cm^-1 at 900°C, respectively. Scanning electron microscopy (SEM) shows that the corrosion resistance increases with increasing the content of NiFe₂O₄. The polarization corrosion rate is bigger than the static corrosion rate due to the oxidation and thermit reaction.