engleski

Protection of CuSn6 bronze from atmospheric corrosion by an imidazole based corrosion inhibitor

The CuSn6 bronze is a copper alloy with good corrosion resistance and strength properties. It is wear-resistant and well solderable and it is good for cold forming. Springs of all kinds, especially for the electrical industry, are made of this bronze. It is used in paper, pulp and chemical industries, shipbuilding and mechanical engineering. When exposed to urban atmospheres copper and its alloys are endangered from corroding with time. Thus additional protection is needed. One possibility of protection is the use of corrosion inhibitors. Previous investigations have shown that imidazole derivatives offer good protection in different media. Potentiodynamic measurements and electrochemical impedance spectroscopy (EIS) were applied to evaluate the inhibitive efficiency of 1-H benzimidazole (BZI) as a corrosion inhibitor for CuSn6 bronze in a Na2SO4/NaHCO3 solution which simulates an urban atmosphere. The investigations have shown that BZI is a mixed corrosion inhibitor with good protective properties. The interaction between the inhibitors and the bronze surface is a combination of physisoption and chemical adsorption. However, after long immersion (over 1 month) the surface colour of bronze changes into a brown-reddish colour. Therefore, this inhibitor cannot be applied at present time to protect objects of which the appereance should not be changed.

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