Electrochemical behavior of nickel in caustic solution and in the presence of chlorine derivatives
Volume Title: 1
1Chemical engineering, mahshahr campus, amirkabir university of technology, tehran, iran
2Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
Corrosion behavior of nickel in caustic soda (NaOH) solution in the presence of chloride and hypochlorite ions was studied. Open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were conducted to characterize the corrosion behavior of nickel electrode. It was found that the chloride ions could not show a tangible effect on the electrochemical behavior of the nickel; however, a higher corrosion rate of nickel in the caustic solution containing hypochlorite was seen compared to that in the caustic without any chlorine-derived components. EIS measurement showed the polarization resistance of 82 kΩ cm2 for nickel in the caustic solution while this value dropped to 0.7 kΩ cm2 in hypochlorite/caustic solution.