Effect of nickel content on the anodic dissolution and passivation of zinc�?�nickel alloys in alkaline solutions by potentiodynamic and potentiostatic techniques

Bulletin of materials science

Hany M Abd El-Lateef¹  Hossnia S Mohran¹  Abdel-Rahman El-Sayed¹ 

[1]Chemistry Department, Faculty of Science, Sohag University, Sohag 82524, Egypt$$Chemistry Department, Faculty of Science, Sohag University, Sohag 82524, EgyptChemistry Department, Faculty of Science, Sohag University, Sohag 82524, Egypt$$

关键词: Metal;    alloys;    anodic dissolution;    passivation;    electron microscopy;    X-ray diffraction.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

The effect of systematic increase of Ni on the anodic dissolution and passivation of Zn�?�Ni alloys in various concentrations of KOH solution (0.1�??1 M) was investigated. The anodic dissolution and passivation behaviour for each pure Zn and Ni in the same studied solutions was also investigated, and the obtained data were compared. Potentiodynamic and potentiostatic methods were used, and the corrosion layer formed on each electrode surface was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results of the anodic potentiodynamic measurements exhibited that the polarization curves showed active/passive transition in the case of Ni and active/pseudopassive in the case of both Zn and its alloys. The results showed that the increase in Ni content increases the activation energy (𝐸_a) and decreases the dissolution rate of the alloys in KOH solution, and the lowest dissolution rate was obtained at 10% Ni. The results of both potentiodynamic and potentiostatic measurements exhibit sudden increase in current density which is observed at certain positive potential (+0.42 V 𝑣���?.SCE) in the case of the investigated alloys. This indicates that the addition of Ni to Zn promotes the electrochemical reaction (in the passive region). However, the passivation potential shifted to more positive direction with the increase in Ni content in the alloy.

【 授权许可】

Unknown