硫酸体系中铅阳极表面氧化膜内应力与电化学性能研究

Internal Stress and Electrochemical Properties of Oxide Film on Lead Anode Surface in Sulfuric Acid System

铅及铅合金作为一种耐蚀性良好的不溶阳极材料,广泛应用于电化学冶金领域,尤其在电解冷轧板生产中具有非常广泛的应用。铅阳极基体的逐渐溶解以及表面二氧化铅膜层的脱落都会对生产造成严重影响。本文以四种铅阳极为研究对象,在0.4mol/L的硫酸根溶液中制备了氧化膜,利用金相显微镜。X射线衍射仪、拉曼光谱仪和电化学测试手段研究了合金元素对氧化膜内应力以及氧电化学性质的影响。结果表明Pb及Pb-Sn-Ag合金氧化膜受PbO和PbO2影响表现为压应力,而Pb-Ca-Sr合金氧化膜的应力则主要受PbSO_4所影响。拉曼光谱测试表明除Pb外其它合金均只有两个峰,说明合金元素的加入对铅基合金在硫酸根腐蚀液中的影响显著。循环伏安、极化曲线和电化学阻抗测试表明Pb的耐蚀性最差而Pb-Ca合金的耐蚀性最强,说明Ca的加入可提高耐蚀性。Mott-Schottky曲线测试结果显示合金元素的加入使半导体类型发生显著变化,Pb-Sn-Ag表现为p型半导体,Pb-Ca由n型半导体转变为p型半导体,Pb-Ca-Sr则处于绝缘状态。

As a kind of insoluble anode material with good corrosion resistance,lead and lead alloy are widely used in the field of electrochemical metallurgy,especially in the production of electrolytic cold rolled sheet.The gradual dissolution of the lead anode matrix and the shedding of the surface lead dioxide film layer show a serious impact on production.In this paper,four lead anodes were used as research objects,and the oxide film is prepared in a 0.4 mol/L sulfate solution using a metallographic microscope.The effects of alloying elements on the internal stress of the oxide film and the electrochemical properties of the oxygen are investigated by X-ray diffractometry,Raman spectroscopy and electrochemical testing.The results show that the Pb and Pb-Sn-Ag alloy oxide films are affected by PbO and PbO 2 and the stress of Pb-Ca-Sr alloy oxide film is mainly affected by PbSO 4.The Raman spectroscopy test shows that except for Pb,there are only two peaks,indicating that the addition of alloying elements has a significant effect on the lead-based alloy in the sulfate etching solution.Cyclic voltammetry,polarization curves and electrochemical impedance measurements show that the corrosion resistance of Pb is the worst and the corrosion resistance of Pb-Ca alloy is the best,indicating that the addition of Ca can increase the corrosion resistance.The Mott-Schottky curve test results show that the addition of alloying elements significantly changes the type of semiconductor.Pb-Sn-Ag shows a p-type semiconductor,Pb-Ca changes from an n-type semiconductor to a p-type semiconductor,and Pb-Ca-Sr is insulated state.