engleski

The Influence of pH on the Copper Corrosion Inhibition in Chloride Media

The influence of solution pH value on the copper corrosion inhibition by 4-methyl-1(4-methoxyphenyl) imidazole has been investigated. The measurements of corrosion rate in the absence and in presence of the investigated imidazole compound, performed by electrochemical methods (Tafel extrapolation and polarization resistance determination), have shown that 4-methyl-1(4-methoxyphenyl) imidazole significantly reduces copper corrosion in acidic and neutral chloride media. The inhibition was most pronounced at pH 2 (92 %) and least pronounced at pH 0 (46 %). At higher pH values the inhibition was limited by the solubility of 4-methyl-1(4-methoxyphenyl) imidazole. The investigated inhibitor retards both cathodic and anodic reaction, which confirms that the investigated imidazole compound acts as a mixed inhibitor. Measurements of pH values of the solution, prior to and after adding the investigated imidazole derivative, have shown that pH increases with the increase of the inhibitor concentration in both acidic and neutral solutions. This can be explained by the protonation of the inhibitor.

copper corrosion; corrosion inhibition; imidazole; chloride media; pH-value

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