Abstract

M. Abdallah^1,2,, M. M. Salem³, I. A. Zaafarany², A. Fawzy^1,4  and A. A. Abdel Fattah¹

DOI : http://dx.doi.org/10.13005/ojc/330621

The electrochemical behavior of nickel, Inconel 600, Incoloy 800 and 316 stainless steel   electrodes in different concentration of NaOH solution  was investigated  using the cyclic voltammetry technique (CV). All the curves in the anodic branch of the CV are characterized by anodic dissolution peak (A),passive region (B),anodic dissolution peak (C) before oxygen evolution. In the case of the  cathodic  branch of CV there is one  reduction peak (D) in case of Ni electrode  but there are two reduction peaks  (D and E)in case  of the three alloys used. All these peaks are explicated. The effect of chloride ion as a pitting agent on the cyclic voltammetry and the potentiodynamic anodic polarization of Ni ,Inconel600,Incoloy800and 316 SS   electrodes in NaOH solution was investigated. As the concentrations of the chloride ions increase the change of the amount of the anodic charge Dq_a increases  and the values of  the pitting corrosion potential are shifted to the more negative direction indicating the breakdown of passivity and the imitation of the pitting corrosion. At one and the same Cl^- ion concentration, the resistance to the pitting attack decreases in the following order: 316SS >  Inconel 600 >  Incoloy 800  > 316 SS. This order depends on the chemical composition of these alloys.

Nickel; Inconel 600; Incoloy 800; 316 SS; cyclic voltammetry; pitting corros

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