Effects of elastic deformation on the anodic dissolution of X70 carbon steel in sulfuric acid solution

Effects of elastic deformation on the anodic dissolution of X70 steel have been investigated in 0.5 mol dm−3 H2SO4 solution. In the active region, the elastic stress exerts no obvious influence on the active dissolution rate of the specimen. However, in the oscillatory region, it leads to a marked increase in the frequency of current oscillations, while the mode remains essentially the same. In the passive region, it induces oscillations at the initial stage, but shows no significant effect on the passive current when the potential is controlled at the more positive stage. Two explanations are postulated: the elastic deformation degrades the stability and increases the defects of the passive film; it increases the surface energy (ΔGS), causing the effective potential (EV) to move negative.

► The anodic dissolution of X70/H2SO4 system is studied under the elastic deformation. ► The frequency of the current oscillations is increased. ► The oscillations are induced at the initial stage in the passive region. ► The passive film on the surface of X70 steel generates an additive tensile stress. ► The external stress degrades the stability of the passive film.