Comparative study on corrosion behaviour of rusted X100 steel in dry/wet cycle and immersion environments

Abstract

A dry/wet cycle corrosion test device was constructed to study the corrosion behaviour of X100 steel under rust layer in dry/wet cycling and immersion conditions. Results showed that the exposure of X100 steel in dry/wet cycle condition with high concentration of Cl−, fast diffusion of O2, and wetness of the rust layers led to an accelerated corrosion process. The initial corrosion rate in the dry/wet cycle environment was higher than that in the immersion environment. As the corrosion time increased, the α-FeOOH content in the rust layer increased, resulting in a decrease in the rate of electrochemical corrosion of metals. In the immersion environment, the corrosion mechanism involved was a typical oxygen-absorbing corrosion mechanism. Under dry/wet cycle conditions, the simultaneous effects of Cl−, O2, and rust layer were studied. The three stages of the wet surface in dry/wet cycle environment were described, and the corrosion mechanism was clarified.