Behaviour of anti-corrosion coatings: comparison of the ageing in real environment in 2 different exposition sites

摘要

The marine environment is considered as one of the most aggressive natural environment. The complexity of this environment allows various possible interactions leading to the degradation of materials. The sea water itself is aggressive, because of its content in ions and in particular in chloride which is known to promote localized corrosion and autocatalytic reactions on metallic materials, and also because of the presence of microorganisms. Microorganisms such as bacteria are forming biofilms which may increase the degradation rate of materials and moreover these biofilms are the initial step for the formation of bio-fouling which can also lead to corrosion, mainly by differential aeration phenomena.The exposition zone is also very important as the degradation mechanisms are different if the materials are fully immersed, placed in the tidal/splash zone, or just expose to a marine atmosphere.rnIn this context, metallic materials are very sensitive to corrosion and should be protected. One of the most efficient ways to achieve it is using anti-corrosion coating.rnThe purpose of this study is to observe the behaviour of the anti-corrosion coatings provided by Hempel in 2 different real conditions:rn1. Offshore conditions: samples were exposed in the Helgoland highland (North Sea, Germany) in the Fraunhofer IWES facilities accessible to the FP7 shared infrastructure project (European project) MariNet.rn2. Port condition: samples were exposed in the port of Pasaia (Cantabrian Sea, Spain)rnThese coatings were applied on a carbon steel substrate, and half of the samples were artificially damaged to investigate a possible delamination of the coating.rnThe main point is to compare the behaviour of the coating in offshore and port condition where the fouling is drastically different and there is the presence of pollution.