Probing the corrosion mechanism of zinc under direct current electric field

The influence mechanism of a direct current (DC) electric field on the corrosion behaviour of zinc in a simulated industrial environment was studied by using weight loss measurement, electrochemical tests, XRD and SEM/EDS techniques. The results show that the corrosion rate of zinc increased with the increase of DC electric field intensities. The main corrosion products formed on the sample in ZnSO4 solution are Zn(OH)2, ZnO, Zn5(OH)6(CO3)2 and Zn4SO4(OH)6.5H2O. It was found that the DC electric field enables OH− and SO42− ions to migrate from the solution/electrode interface to the upper layer of the solution quickly. Thus it can change the reaction site of the formation of Zn4SO4(OH)6.5H2O and can increase the quantity of the porous hexagonal plate Zn4SO4(OH)6.5H2O. All these features can promote the corrosion rate of zinc. •Effect of DC electric field on the corrosion of zinc in ZnSO4 solution was studied.•DC electric field enhanced the corrosion of zinc in industrial environment.•Structure of corrosion products can be changed with DC electric field.•Ions migration by DC electric field promotes oxygen reduction thermodynamically.•Anodic dissolution process of zinc can be accelerated with DC electric field.