engleski

Comparison of the protective properties of fatty acid films prepared by different application methods

Global efforts in environment protection also require the development of non-toxic technologies in the field of corrosion protection, like development of waterborne coatings or green corrosion inhibitors. In line with that, the corrosion protection by fatty acids seems like an interesting choice for metal protection. Our previous studies showed that films of stearic acid, formed by dip-coating method on the surface of cupronickel alloy provide efficient corrosion protection in chloride media [1, 2]. In this work stearic acid films are formed on the surface of cupronickel alloy and stainless steel by three different methods: dip coating, spraying and electrochemical method. Their protective properties are examined by electrochemical methods: polarization measurements and electrochemical impedance spectroscopy. The obtained results show that for all three application techniques a proper choice of film application conditions, such as temperature, duration or surface preparation, results in formation of stearic acid films that efficiently protect both studied alloys. This is also confirmed by SEM studies of protected samples exposed to corrosive medium. Generally, the highest initial corrosion protection is achieved by spray coating method which is attributed to the formation of the thickest protective layer. However, after exposure to corrosive medium protection offered by films, formed by spraying, declines while that of the films formed by dip-coating and especially by electrochemical method remains high. Besides the electrochemical studies, obtained films are characterized by FTIR and Raman spectroscopy and contact angle measurements. In the case of dip-coating and spraying methods formation of ordered layers of stearic acid is assumed, while in the case of films formed by electrochemical method formation of ordered stearate layers is proposed

corrosion protection ; electrochemical measurements ; Self-assembled organic monolaye

nije evidentirano