Effect of additive BaO on corrosion resistance of xCu/(10NiO-NiFe 2O 4) cermet inert anodes for aluminum electrolysis

Abstract

xCu/(10NiO-NiFe 2O 4) cermet and 1BaO- xCu/(10NiO-NiFe 2O 4) cermet ( x=5, 10, 17) inert anodes were prepared as potential inert anodes for aluminum electrolysis and their corrosion resistance to traditional electrolyte was studied with anodic current density of 1.0 A/cm 2 in laboratory electrolysis. The substantial corrosion of metal Cu was observed, many pores appeared on the surface of anode and electrolytes infiltrated inside anodes during the electrolysis. The wear rates of 5Cu/(10NiO-NiFe 2O 4), 10Cu/(10NiO-NiFe 2O 4), 17Cu/(10NiO-NiFe 2O 4), 1BaO-5Cu/(10NiO-NiFe 2O 4), 1BaO-10Cu/(10NiO-NiFe 2O 4) and 1BaO-17Cu/(10NiO-NiFe 2O 4) are 2.15, 6.50, 8.30, 4.88, 4.70 and 4.48 cm/a, respectively. The addition of BaO to 10Cu/(10NiO-NiFe 2O 4) cermet and 17Cu/(10NiO-NiFe 2O 4) cermet is advantageous because BaO can effectively promote densification and thus improve corrosion resistance. But the addition of BaO to 5Cu/(10NiO-NiFe 2O 4) cermet is unfavorable to corrosion resistance because additive BaO at the grain boundary of anode accelerates possibly the corrosion of cermet.