Nickel Plating Bath Voltage Selectivity: Useful but Risky

Summary for nickel plating bath voltage selectivity Discussion

Nickel plating bath voltage selectivity is the key issue here: Ivan Horban reported that a bath he thought was nickel acetate plated nickel at 1.5 V but copper at 1.0 V, and later found it was a mixed copper-nickel solution. The reply explains that this can happen because a nickel bath contaminated with copper can be selectively stripped of copper by plating at low voltage, which deposits much more copper than nickel. The answerer notes that old nickel plating tanks sometimes used a built-in "electropurification compartment" to continuously remove copper onto scrap at low voltage. However, the advice is cautious: a bath heavily contaminated with copper is unlikely to produce a very satisfactory nickel finish, though continuing at about 1.0 V may reduce the copper content over time.