Corrosion Behaviour of Galvanised Products

Abstract

On tonnage basis atmospheric corrosion of metals and alloys is one of the serious corrosion problems in the modern civilization because of its considerable effect on GNP of the country. The commonest cause of rapid atmospheric corrosion is the presence of acidic gases, such as sulphur dioxides, hydrogen sulphide or hydrogen chloride or of suspended salts like ammonium sulphate or sodium chloride . The acidic gases resulted on with the rapid industrialization, pose enormous corrosion problem if it is unchecked . Generally, the atmospheric corrosion is minimised by ( i) eliminating corrosion constituents from the atmosphere , ( ii) selecting a material posse-ssing maximal resistance or (iii) by interposing a prot-ective coating in between the metal and the corrosive atmosphere . Methods based on avoiding atmospheric poll-ution and selecting an atmospheric corrosion resistance metals and alloys have their limitations on practical as well as on economic grounds . So, interposition of a protective coating in between the metal and the corrosive atmosphere is considered most appropriate in view of its case of application and economic benefits.