The Pb oxide and Ru oxide films with various compositions were prepared by reactive sputtering using mixed gas of Ar and O
2, and those anodic polarization properties were investigated in a 150 g L
-1 H
2SO
4 solution at 303–333 K. When O
2 amount of the Ar-O
2 mixed gas was 25 vol.% or more, the product thin films were identified as mixed phase of α-PbO
2 and β-PbO
2 for the reactive sputtering of Pb target. On the other hand, the products were single phase of RuO
2 for the reactive sputtering of Ru target at the same O
2 amount of the mixed gas. The anode potential of the metallic Pb thin film was equal to that of the PbO
2 thin film at the current density of 10 mA cm
-2 or more. So, it can be judged that the surface of the Pb-based alloy anode was covered with the PbO
2 at 60 mA cm
-2, which is a typical current density during the operation of zinc electrowinning, and the oxygen evolution overpotential of the PbO
2 determined the bath voltage of the electrowinning. Moreover, the anodic polarization measurement showed that the anode potential of the RuO
2 at 60 mA cm
-2 was about 560 mV lower than that of the PbO
2. Therefore, the remarkable decrease of the anode potential for the Pb-based powder rolling anode, in which the RuO
2 powders were dispersed in the Pb substrate, was probably due to an extremely low oxygen evolution overpotential of the RuO
2 in itself.
抄録全体を表示