EQCM study on corrosion of iron thin film in deaerated neutral solutions

The corrosion behavior of iron thin film in deaerated neutral solutions is investigated via an electrochemical quartz crystal microbalance. The iron thin film with a thickness of 200 nm is electroplated on the gold electrode of quartz crystal. The dissolution of iron thin film at the natural immersion in pH 6.48 borate solution is promoted by the circulation of the solution. The dissolution rate at the natural immersion is higher in circulated phosphate solution than in circulated borate solution in spite of the same pH value of 6.48. The net current that flowed through the external circuit during galvanostatic polarization near the corrosion potential is successfully separated into the iron dissolution current and hydrogen evolution current. The corrosion mechanisms of borate and phosphate solution is discussed from the Tafel slopes.