Metal removal rate of the electrochemical mechanical polishing technology for stainless steel - the electrochemical characteristics

摘要

Electrochemical mechanical polishing technology was studied in this research in order to investigate the effects of electrochemical parameters such as the electrolyte, pH values, and operating potential on the metal removal rate of polishing AISI 316L stainless steel (SS316L). The dynamic polarization curve method was employed to evaluate the effects of the compositions of electrolyte (phosphoric acid and H{sub}2O{sub}2) and electrochemical parameters (pH values, H{sub}2O{sub}2 concentration, and operating potential) on the metal removal rate of SS316L. The results showed that SS316L, in the lower-pH-value electrolyte solution, will have a shorter passive region and higher current densities of both passive and trans-passive regions. The concentration of hydrogen ions was higher at lower pH values, resulting in damage of the passive film. The H{sub}2O{sub}2 additive will also release hydrogen ions which will accelerate the reaction. Thus, the passive region was severely shortened. However, the H{sub}2O{sub}2 will also release OH{sup}- ions. Therefore, the pH value of the electrolyte will increase slightly, and the current density in the trans-passive region decrease slightly. The electrochemical reactions were strong (higher metallic dissolution rate) at pH 2 solution. Therefore, the metal removal rate was higher. An appropriate amount of H{sub}2O{sub}2 additive (6 vol %) may also improve the electrochemical reactions and increase the polishing efficiency.