Corrosion of steel in presence of borate ions in aqueous solutions

Anodic and cathodic polarization measurements for the corrosion of steel in aqueous solutions containing various concentrations of boric acid and sodium borate have been studied poteutiodynamically. Open circuit potentials for the corrosion of steel electrode in the mentioned solutions at 303 K become more negative with increasing pH in the anodic region. At sufficiently anodic potentials, in presence of borate ions, passivation characteristics were obtained. Cathodic Tafel slopes for the hydrogen evolution reaction (h.e.r) on steel for the different solutions were determined. The presence of borate ions in the solution leads to the formation of Fe complex during anodic polarisation which is sparingly soluble at low pH value and causes passivation.