Atmospheric Corrosion of Engineering Materials at Two Exposure Sites in Chennai—A Comparative Study

Atmospheric corrosion of engineering materials such as mild steel, galvanized iron, zinc, and aluminum at marine and industrial environments in Chennai has been studied. Monthly and yearly corrosion rates were determined using the weight-loss method. The average levels of pollutants, viz., salinity and sulfur dioxide (SO₂), in both atmospheres have been measured. The results of five-year corrosion exposure tests agree well with the kinetic equation of the form V_corr = ktⁿ, where k and V_corr are the weight losses after 1 and “t" years of the exposure, respectively, and n is a constant. Based on the n value, the corrosion mechanisms of these metals have been predicted. The corrosion products of the materials were analyzed using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques.