Corrosion Monitoring of Fe-Cu Alloys under Different Drying Times and the Effect of Copper on Their Corrosion Rate

In this study, an alternating current (AC) impedance technique was applied in the monitoring of corrosion rates of iron and Fe-Cu (0.4, 3 mass%) alloys in a wet/dry cycle condition. Drying for 3 h and 5 h under wet/dry conditions was used. The corrosion rates of pure iron were greatly accelerated by the wet/dry cycles. The increase in drying time from 3 h to 5 h resulted in aggressive corrosion rates. This result could be explained by the acceleration of oxygen transport through the thin electrolyte layer. In contrast to iron, the Fe-3mass%Cu alloys showed low corrosion rates. Even during the drying period, the 3mass%Cu showed a clear passivation.