M.M. Ahmed *

Chemistry Department, College for Girls, Ain Shams University,  Cairo, Egypt

Received 8 June 2004; accepted in revised form 2 February 2006

 Abstract: The corrosion behaviour of Zn – Al – Cu alloy was studied in pure HCl solutions and in the presence of different concentrations of inhibitors. The techniques of measurements were: weight loss, linear polarization, polarization impedance and corrosion penetration. It was found that the corrosion rate of this alloy is greatly higher than that of Zn or Al. The inhibitors used were: heterocyclic pyridine (p), 2-methyl pyridine (2 mp), 3-methyl pyridine (3 mp) and 4-methyl pyridine (4 mp). These inhibitors behave as mixed type and their inhibition efficiency increases according to the order: 2 mp < 3 mp < p <4 mp. The values of activation energy of corrosion were determined in pure acid and in the presence of inhibitors. It was found that the presence of these inhibitors increases the value of activation within the same order of their inhibitory effect. The adsorption of the investigated inhibitors on the surface of the alloy follows Frumkin’s isotherm.

Keywords: corrosion, zinc alloy, heterocyclic pyridine, galvanostatic polarization, impedance.

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* Corresponding author. E-mail address: drsohairr@hotmail.com