Effect of Soil Moisture on Corrosion Behavior of Zinc in Simulated Soil Environment

Abstract

In this study, the corrosion behavior of zinc in a simulated soil environment was investigated at various degrees of saturation, S_r by using surface observation, corrosion depth analysis, electrochemical impedance spectroscopy, and potentiodynamic polarization tests to evaluate the effect of soil moisture on corrosion morphology and corrosion rate and of zinc. At high soil moisture content （S_r＞80％）, the average corrosion rate of zinc remained low and did not change much with S_r. On the other hand, at low moisture content （S_r＜80％）, the average corrosion rate increased significantly and showed a peak at around S_r＝50％. In addition, the corrosion morphology of zinc became more heterogeneous with decreasing S_r, indicating that the corrosion depth became deeper. The effects of soil moisture on the corrosion morphology and corrosion rate of zinc were discussed based on the changes in cathodic reduction of oxygen and anodic reaction of zinc in a simulated soil environment.