Eco-friendly oxalic acid and citric acid mixed electrolytes using for plasma electrolytic polishing 304 stainless steel

Abstract

The traditional of mixed electrolyte of H2SO4 and H3PO4 widely used in electropolishing 304 stainless steel. Due to environmental protection and safety issues, there is an urgent need to develop more environmentally friendly electrolytes. In this study, 304 stainless steel was electropolished by plasma electropolishing using a mixed electrolyte of oxalic acid and citric acid, which are environmentally friendly electrolytes. The mixed electrolyte concentration of oxalic acid and citric acid were 0.01 M, 0.05M, 0.1M, 0.3M and 0.5 M, respectively. The volume mixing percentage is adjusted to about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8, respectively. Plasma power is about 1.3 kW, electrolysis time is 5 and 1 minutes, respectively. The results show that low-concentration mixed electrolyte, shortened electrolysis time and proper electrolyte mixing ratio, can obtain better surface roughness. The mixing ratio of oxalic acid and citric acid mixed electrolyte, and the factors that may affect the surface roughness of plasma electropolished 304 stainless steel, will be discussed in the text.