Abstract: | Corrosion inhibitors 25(1) – The role of the cation in a neutral salt in the corrosion of iron in the presence of oxygen The rate of uptake of oxygen, under standard conditions, in the corrosion of 500 mg DAB6 iron powder is dependent on the nature of the cation in a neutral salt (chloride). In the presence of alkali, quaternary ammonium, quaternary phosphonium and alkali-earth chlorides, the rate of oxygen uptake is comparable. With zinc, cadmium, nickel and cobalt chlorides a marked decrease in the oxygen uptake is observed between pH5 and pH7. This is probably due to a block in the cathodic area in the iron boundary layer through precipitation of the rather insoluble basic hydroxides of zinc, cadmium, nickel and cobalt. |