Effect of Air Pollution on Atmospheric Corrosion of Engineering Metals

Abstract

Atmospheric corrosion is probably the most common form of corrosion and is defined as the corrosion or degradation of material exposed to air and its pollutants. This study essentially deals with atmospheric corrosion to assess the degrading effects of air pollution on various metals most used in engineering systems. This was the first ever corrosion study to be carried out in Oman concerning the influence of air pollution on atmospheric corrosion of metals. Common materials such as aluminum, brass, copper, epoxy, galvanized iron, mild steel, and stainless steel were used for the study. The selected sites of exposure were five locations where the metals were likely to be used. The results are discussed as functions of the type of test material, test location, environmental pollution factors, and exposure time. The results indicate that copper and mild steel are the most corrosive metals, while stainless steel, aluminum and epoxy are the least corrosive. Of the locations, Sohar emerged as the site with the worst corrosion record. Furthermore, higher concentrations of chlorides were observed in the Airport and Sohar areas, which are close to the seacoast. The highest carbonate sites were located in Al-Rusail and Sohar areas, these being more polluted industrial areas. Moreover, it was found that the atmosphere in the Al-Fahl area was polluted with sulphur compounds. In general, the results of this study can be used to obtain a corrosion fingerprint of the locations included herein.