Effects of Hydrogen and Chloride Ions on Automobile Interstitial-Free Steel Corrosion

Effects of hydrogen and chloride ions on the corrosion behavior of interstitial-free steel were investigated. The anodic polarization tests show that the corrosion and pitting potentials decrease with the rise of both the charging current density and the chloride ions concentration. For a given chloride ion concentration, the increase of the charging current density makes the pitting and the corrosion potentials drop sharply. Under a given hydrogen charging current density, the drops of the pitting and corrosion potentials have an approximately linear relationship with the increase of the chloride ions' concentration. It indicates that the hydrogen and chloride ions can affect the corrosion behavior. From the salt fog tests, the growth and development of the rust and pits on the hydrogen-charged specimen are faster than that of the uncharged one, displaying that hydrogen can decrease the corrosion resistance in the chloride ions' environment.