The influence of strain on the passive behavior of carbon steel in cement extract

The influence of strain on the passive behavior of carbon steel in simulated concrete pore solution was studied. The results show that as strain magnitude increases, the passive current density and passive rate of carbon steel increase, but current fluctuations occur, which indicates that the passive film tends to be unstable with increased strain. The donor density in the passive film increases with the increase in strain magnitude while the ratio of Fe3+/Fe2+ in the passive film decreases. These changes might explain the effects of strain on the passive rate and the stability of the passive film.

► The effect of strain on passive stability of steel in cement extract is studied.
► The passive rate increases but the passive film is unstable with increasing strain.
► As the strain magnitude increases, the donor density in the passive film increases.
► The ratio of Fe3+/Fe2+ in the passive film decreases with increased strain.
► The reduced passivity is due to increased oxygen vacancy and Fe2+ contents in film.