N- Benzylidene : A new and effective corrosion inhibitor for copper in hydrochloric acid solution

چکیده مقاله

Copper is widely used for industrial applications due toits excellent electrical and thermal conductivities and good mechanicalworkability [1]. Copper is resistant to the influence ofatmosphere and many chemicals. To improve thecorrosion resistance properties of copper, great efforts have beengives to the investigations [2].One suitable approach to minimizing corrosion damage is to use corrosion inhibitors which are substance used in very low amounts that efficiently slow the rate of corrosion. Heterocyclic organic compounds containing sulphur and/ornitrogen heteroatoms which are available for bonding with metalsurface are commonly used as inhibitors. N-benzylidenederivatives are illustrious due to their goodinhibitor efficiency in various media. The inhibition effect of two N- Benzylidene derivatives namely N-(4,5dicholoromethylbenzylidene) Pyridin – 2 amine amineand N-(4-choloromethylbenzylidene) Pyridin – 2 amine have been investigated against the corrosion of copper in 6.0 M HCl solution. Corrosion inhibition behavior were investigated by electrochemical impedance spectroscopy (EIS), electrochemical polarization measurement and quantum chemical studies. Among the studied compounds, N-(4-choloromethylbenzylidene) Pyridin – 2 amine exhibited the best inhibition efficiency 96% at 0.01 M. The EIS results show that equivalent circuits of blankand inhibitors are fitted with theRQRW and RRQ modes, respectively. The results demonstrated that the investigated compoundsbehave as good inhibitors for copper corrosion in acidic solution.Their efficiency increases with increase in concentration from 0.0005 M to 0.01 M. The results of potentiodynamic polarization show that N-benzylideneare cathodic type inhibitor. Adsorption of these compoundsobeyed the Langmuir adsorption isotherm. The electronic properties obtained using quantumchemical approach, were correlated with the experimental results.