engleski

The impact of microorganisms on the corrosion protection by self-assembled layers of phosphonic acids in natural waters

The microbiologically influenced corrosion can cause problems where ever natural water is present (e.g., in cooling towers, in drinking water pipelines, in sewage systems as well as in the food industry, on ship halls, and in oil production). Although highly resistant alloys are used for designing these plants, MIC has been shown to occur on a number of materials, including conventionally used structural materials such as stainless steels and cupronickel alloy. It is therefore of great importance to develop antibacterial coatings that are stable, environmentally benign, and provide good corrosion resistance to improve alloys performance under corrosive condition. Since many commercial corrosion inhibitors are ecologically unsuitable due to their toxic impact on the ecosystem, the application of self-assembled mono- and multilayers presents potential ecologically suitable solution for increasing a corrosion resistance of alloys. The aim of this work is to investigate the possibility of stainless steel and cupronickel alloy protection by self-assembled layers of octadecylphosphonic acid prepared by spraying method. Behavior of unprotected metals in natural medium, Sava river water and seawater, and in tentatively sterilized water by membrane filtration method was followed simultaneously in order to differentiate to which extend the corrosion is influenced by microorganisms. In the same conditions the behaviour of samples modified with phosphonic acid was studied. The protective properties of such formed layers are examined during a time period of 40 days by linear polarization resistance method while the examination of the metal surfaces is conducted by optical and scanning electron microscopy.

natural water ; microbiologically influenced corrosion ; biofilm ; long-chain phosphonic acid ; self-assembled layers

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