Corrosion of Mild Steel by Ferrous Sulphide

The rate of corrosion and total corrosion of mild steel in the presence of chemically prepared ferrous sulphide has been studied. The mild steel appears to corrode by a first order reaction. Continued high corrosion rates are observed in experiments where ferrous sulphide is added semi-continuously. Approximately 10 mg iron are corroded by 1 m mol of ferrous sulphide (88 mg) at pH 7. pH has only a small effect on the total corrosion. The presence of CO2 modifies the corrosion rate, but not the total corrosion. Two possible corrosion mechanisms are discussed.