Effect of Cu, Mn on the Corrosion Performance of Carbon Steels in Wet/Dry Environments

The atmospheric corrosion performance of Mn - and Cu - bearing steels was studied by dry/wet cycb'c corrosion tests (CCT) with 60% relative humidity at 30 ℃. The salt droplet used for CCT was 0. 3% NaCl solution. The rusted specimens were investigated by gravimetry, electrochemical techniques and XRD analysis. The results showed that the steel containing 0. 30%Cu showed higher corrosion resistance than plain carbon steel due to the accelerated rust reduction in cathodic region, which facilitated the formation of the inner rust layer containing more Fe3O4. While the 1. 43 % Mn - bearing steel showed a worse corrosion resistance than carbon steel owing to the depressed cathodic reduction and accelerated dissolution of iron in anode.