XRD and SEM studies of the layer of corrosion products for carbon steel in various different environments in the province of Las Palmas (The Canary Islands, Spain)

Abstract

A study was carried out in order to identify the various elements which make up the layer of rust which is produced on carbon steel exposed to the atmosphere in the province of Las Palmas (The Canary Islands, Spain). XRD and SEM analyses were used in order to identify and describe the various corrosion products produced over different areas on the islands: rural, urban, marine and marine-industrial. The main product found was akaganeite, which is typical of marine areas, followed closely by lepidocrocite, goethite and magnetite. Likewise, another formerly unidentified corrosion product for carbon steel, such as is green rust II, was detected. It has been found that the protective capacity of corrosion products increases over the first year of exposition and then levels off.Likewise, a hyperbolic law was used to model the protective effect of the layer of corrosion products which gave extremely good regressive values both in the case of each station individually and when grouped together by corrosion category (r(2) > 0.98). (C) 2002 Published by Elsevier Science Ltd.