Influence of Na2SO4-electrolyzed reduced water on the surface of pure aluminum

This paper describes the influence of Na2SO4-electrolytic reduced water (hereinafter referred to as ER water) on pure aluminum. First, the etching action of Na2SO4 ER water on the surface of pure aluminum was clarified by the etching test using immersion. The comparative study showed that Na2SO4 ER water was superior to chemical solution or Na2SO4-electrolytic oxidizing water in etching action, and the stronger electrolytic current value becomes, the stronger the etching action of Na2SO4 ER water becomes. Next, by the observation using FE-SEM image, the influence of Na2SO4 ER water on the micro shape of the surface of pure aluminum was clarified. The results showed there was not a difference between the micro shape of the sample piece done by Na2SO4 ER water and the one done by NaOH solution, and even in either case the alien substance appears on the surface of sample pieces. Lastly, by analyzing the surface using EDS, the influence of Na2SO4 ER water on the chemical composition of the surface of sample pieces was clarified. The results showed Na2SO4 ER water and NaOH solution are similar level. By this study, we received the suggestion that Na2SO4 ER water could be applied to the surface treatment such as the etching of pure aluminum. © 2020 Japan Society for Precision Engineering. All rights reserved.