Influences of temperature, H2SO4 concentration and Sn content on corrosion behaviors of PbSn alloy in sulfuric acid solution

The influences of temperature, H₂SO₄ concentration and Sn content on corrosion behaviors of PbSn alloys in sulfuric acid solution were investigated by potentiodynamic curve, cyclic voltammetry (CV), linear sweeping voltage (LSV), electrochemical impedance spectra (EIS), a.c. voltammetry (ACV) and Mott-Schottky analysis. The microstructure of the corrosion layer on PbSn alloy was analyzed by scanning electron microscopy (SEM). The results showed that the corrosion resistance of PbSn alloy increased with ascending Sn content and H₂SO₄ concentration, the increment of temperature can decrease the corrosion resistance of PbSn alloy in H₂SO₄ solution. The conductivity of the anodic film on PbSn alloy was enhanced with increasing temperature, ascending Sn content and descending H₂SO₄ concentration. SEM result revealed that the corrosion film after cyclic voltammetry was consisted of tetragonal crystal, the porosity enlarged with decreasing temperature, Sn content and H₂SO₄ concentration.