| 摘要 |
PROBLEM TO BE SOLVED: To provide an aqueous electrolyte solution with which the use of strong acids in metal finishing baths can be reduced.SOLUTION: This invention relates to an aqueous electrolyte solution, including: citric acid in a concentration range of about 1.6 g/L to about 982 g/L; and an effective concentration of ammonium bifluoride (ABF), wherein the electrolyte solution is substantially free of a strong acid. This invention further relates to methods of treating a surface of a non-ferrous metal workpiece, including the steps of: exposing the surface to a bath of an aqueous electrolyte solution that includes the citric acid in the range of about 300 g/L or lower and ammonium bifluoride in a concentration range of about 10 g/L or larger, and has about 3.35 g/L or lower of a strong acid; controlling the temperature of the bath to be about 54°C or larger; connecting the workpiece to an anodic electrode of a DC power supply and immersing a cathodic electrode of the DC power supply in the bath; and applying a current across the bath.SELECTED DRAWING: None |
