Effect of stray current coupled with chloride concentration and temperature on the corrosion resistance of a steel passivation film
Pangang Wu, Xingji Zhu, Longjun Xu, Wenshan Peng, Guochen Zhao
Abstract
The combined effects of stray current, chloride ion concentration and temperature on the corrosion resistance of a steel passivation film were studied by electrochemical methods. Potentiodynamic polarization tests and other auxiliary tests were carried out to reveal the mechanism of damage to a steel passivation film. The experimental results indicate that the film becomes unstable under the influence of high voltage stray currents. This leads to a decrease in the threshold chloride concentration and breakdown potential in the depassivation process. High temperature can obviously reduce the thickness of the passivation film, which aggravates damage by chloride ions. However, high voltage plays the decisive role in the destruction of the passive film, and the adverse effect of coupling is much greater than that of a single factor.