Surface Modification of Pure Nickel Materials Using NaCl Electrolytic Oxidizing Water

This paper discusses the surface modification processing of pure nickel using NaCl-electrolytic oxidizing water (hereinafter it is referred as NaCl EO water). Firstly, while comparing with HCl solution, the etching experiments were carried out by immersion in NaCl EO water with or without ultrasonic. The results showed that compared with HCl solution, NaCl EO water has a stronger etching effect on the surface of pure nickel, and the etching effect becomes even stronger when with ultrasonic. And the etching effect on the surface of pure nickel is greatly affected by the concentration of dissolved oxygen (DO) and the concentration of dissolved chlorine (DChl) in the immersion solution. Next, the effect on the chemical composition of the surface layer of test pieces was examined by surface analysis. The results showed the natural oxide film on the rolled surface of pure nickel can be removed by immersing it in NaCl EO water as well as in HCl solution. A very small amount of Cl was detected on the outermost surface of the test pieces immersed in NaCl EO water. Finally, the roughening effect on the polished surface of pure nickel was examined. The results showed that compared with HCl solution, NaCl EO water has a stronger roughening effect, which becomes even stronger when with ultrasonic. By this study, we received the suggestion that NaCl EO water could be applied to the surface modification processing of pure nickel.