The corrosion evolution of carbon steel exposed to an actual industrial atmosphere was investigated. The characteristics of the rust that formed on the steel were analysed by mass-loss measurement, X-ray diffraction, scanning electron microscopy and electrochemical techniques. Mass-loss results showed that the long-term corrosion kinetics of carbon steel can be divided into four stages, and that the corrosion rate varies during the different corrosion stages. This corrosion-rate fluctuation is attributed to the increase in the ambient temperature and the change in the composition of the rust layer formed on the steel surface. The reciprocal of charge transfer resistance (R_ct) can be used to represent the corrosion rate. The backward-facing specimens were found to be more suitable as the objects to investigate the corrosion evolution. The evolution of the rust layer that formed on the steel is also discussed.

The evolution of atmospheric corrosion of 316 stainless steel subjected to a simulated marine atmosphere was investigated by scanning electron microscopy, optical microscopy, X-ray photoelectron spectroscopy, and electrochemical measurements. The results indicate that the initiation of pits is associated with the dissolution of MnS inclusion; the maximum pit depth of 316 stainless steel increased in linear relationship with the extension of corrosion time; the corrosion products possess more hydroxide; the ratio of [Cr]/{[Cr]+[Fe]} in the corrosion products gradually increases with increasing time. The protective ability of corrosion products formed on 316 stainless steel has also been discussed.