engleski

Protection of Cu70Ni30 Alloy by Fatty Acids

Cupronickel alloys are often used for applications in marine environment due to their relatively high corrosion resistance based on the formation of protective oxide layer. Their service life in such aggressive environment can be prolonged by protection with corrosion inhibitors. However, marine environment is sensitive to toxic compounds that are often used as corrosion inhibitors. For this reason it is very important to develop new corrosion inhibitors that are not harmful to marine ecosystems. Fatty acids are known to adsorb on some of the metal oxides and form self- assembled monolayer that might act as a barrier to diffusion of aggressive species towards metal surface. They are also environment friendly compounds. The objective of this study is to examine several fatty acids as possible corrosion in- hibitors for Cu70Ni30 alloy in seawater. Protective layer is formed by immersion in ethanol solution of fatty acid. Influence of the application conditions, such as immer-sion time, fatty acid concentration, temperature and surface pretreatment, on inhibit-ing efficiency and stability of fatty acids monolayer is examined. Studies are performed by electrochemical methods: polarization measurements and electrochemical impedance spectroscopy. Results of this investigation show that fatty acids increase the corrosion resistance of cupronickel alloys and prolong their service life in seawater.

Cupronickel alloys; fatty acids; self-assembled monolayers; marine corrosion

nije evidentirano