A MECHANISTIC STUDY OF THE EFFECT OF ENVIRONMENTAL CONDITIONS IN CHINA, SOUTH-EAST ASIA AND AUSTRALIA ON THE CORROSION OF ZINC AND STEEL

摘要

Traditional studies of corrosion of metals in polluted environments have concentrated on the effect of gaseous sulfur compounds, and have established relationships between corrosion rates and the gaseous SO_x level in the atmosphere. However, recently it has become apparent that the interaction of metals with the environment is significantly more complex than indicated from these early models. Not only must a range of acid precursor gases be considered, but also alkali precursor gases (notably NH_3), oxidants and particulate deposition must be considered. To study this more complex interaction between metallic corrosion and the environment, a large number of sites were established in China, Vietnam, the Philippines, Indonesia, Thailand and Australia. At the majority of these sites, gaseous NO_x and SO_x, particulate chemistry and deposition rate, TOW, RH and plate surface temperature were measured. Further, steel and zinc plates were exposed and examined to determine both mass gain on exposure, mass loss after cleaning, and morphology and chemistry of oxide layers via FTIR and SEM-EDS. From this data the possible role of particulates in promoting atmospheric corrosion is assessed.