Pb-0.3%Ag-0.06%Ca三元合金阳极在锌电积过程中的电化学行为—循环伏安曲线研究

Electrochemical Behaviors of Pb-0.3%Ag-0.06%Ca Rolled Alloy Anode During and After Zinc Electrowinning—— CV Investigations

Pb-0.3%Ag-0.06%Ca三元轧制合金阳极在酸性硫酸锌溶液中进行了360 h(15 d)的恒电流极化.通过循环伏安技术研究分析了恒电流极化过程中合金阳极的电化学行为的变化.通过X射线衍射技术分析了合金阳极在恒电流极化过程中形成的氧化膜物相.结果表明:合金阳极的阳极氧化膜形成和稳定需要一个过程.在这个过程中,电化学行为和氧化膜物相呈现明显的变化.随着恒电流极化时间的延长,阳极峰(Pb→PbSO4)的强度在前两天的电解中显著升高,其后保持在稳定状态(0.25 mA/cm2),同时向正方逐渐移动.然而阳极峰(PbSO4→β-PbO2,PbO→α-PbO2)却显著地向负方向移动.阴极峰(β-PbO2和α-PbO2→PbSO4)和(PbO和PbSO4→Pb)呈现一个逐渐增加的趋势,同时逐渐的向负方向移动.而且合金阳极氧化膜的腐蚀物相主要为PbSO4、α-PbO2、β-PbO2、PbS2O3和Pb.随着电解时间的延长,PbSO4峰逐渐变弱,α-PbO2峰逐渐增强.PbSO4择优取向为(021)、(121)和(212)晶面.α-PbO2的择优取向为(111)晶面.

In this paper, electrochemical behaviour of Pb - 0. 3% Ag - 0. 06% Ca rolled alloy anode during the 360 hours（ 15 days） galvanostatic electrolysis in acid zinc sulphate electrolyte solution is investigated with Cyclic Vohammetry （CV） techniques. The phase composition of the anodic oxide layers during the electrolysis is ob- served using X-Ray Diffraction （XRD）. The results reveal that the electrochemical oxidation processes and phase formation vary obviously during the electrolysis for it is a process indicating the formation and stabilization of anodic oxide layer. With the increasing electrolysis time, the anodic peak （ Pb→PbSO4 ） mainly presents a rise trend in the first two days electrolysis. It keeps thereafter almost a constant value （0. 25 mA/cm2 ）. The anodicpeak （Pb→PbSO4 ） gradually moves in the positive direction while the anodic peak （PbSO4→q3 -PbO2, PbO→a→PbO2） strongly moves in the negative direction. The cathodic peak（ [3- PbO2 and a- PbO2→PbSO4 ） and （PbO and PbSO→Pb） mainly present a rise trend and gradually move in the negative direction. Besides, the corrosion phase of the anodic oxide layers mainly consists of PbSO4, a - PbO2, β - PbO2, PbS203 and Pb. With the increase of electrolysis time, the content of PbSO, presents a declining trend while the content of a - PbO2 a rising trend. The preferred growth orientation of PbSO4 anda -PbO2 is （021）, （121）, （212） and （111） planes respectively.