Electrochemical investigation of corrosion and corrosion inhibition of copper in NaCl solutions

Inhibition effect of a new pyrimidine heterocyclic derivative, namely 2-hydrazino-4-(p-methoxyphenyl)-6-oxo-1,6-dihydropyrimidine-5-carbonitrile (HPD) on copper corrosion in 3.5% NaCl solutions at 25°C ±1 was investigated by using potentiodynamic polarization , electrochemical impedance spectroscopy, EIS and electrochemical frequency modulation, EFM. The electrochemical measurements demonstrated that, under the chosen experimental conditions HPD offers sufficient inhibition against copper corrosion in 3.5% NaCl solutions. Tafel polarization studies have shown that the HPD suppresses both the cathodic and anodic processes and thus it acts as mixed-type inhibitor. The results of EIS indicate that the value of CPEs tends to decrease and both charge transfer resistance and inhibition efficiency tend to increase by increasing the inhibitor concentration. EFM can be used as a rapid and non destructive technique for corrosion rate measurements without prior knowledge of Tafel constants. Molecular dynamic simulations are performed to investigate the adsorption behaviour of HPD on copper surface.