The Effect of Oxygen on Inhibition of Corrosion by Nitrite

A study has been made of the effects of the concentration of dissolved oxygen and temperature on the rate of breakdown of sodium nitrite in the presence of steel, and on the rate of corrosion of the steel. It was found that, at any given temperature, an increase in concentration of oxygen decreased the amount of nitrite required for inhibition. At high temperatures and low oxygen concentrations it was found that although the rate of corrosion was appreciable the rate of nitrite breakdown was low. In some cases, a considerable time interval before the start of breakdown of nitrite was noted. It was concluded that the mechanism proposed previously for inhibition by nitrite was further substantiated by the evidence presented here.