No.4（2001）5.Nickel electroplating bath using citric acid in place of boric acid

Tadashi DOI, Kazunari MIZUMOTO, Masashi KAYASHIMA and Shin-ichi TANAKA

A new nickel electroplating bath, called a "Nickel citrate bath", uses citric acid in place of boric acid. In order to clarify its properties, a Hull cell test and measurements of current efficiency and pH titration curves were performed. The results were compared with those obtained from a Watts bath. The citric acid in a Nickel citrate bath consists of various ratios of citrate ion and nickel-citrate complexes, forming complex equilibrium at various pH levels. A Nickel citrate bath with a concentration of citric acid above 0.06M has good appearance, current efficiency, and pH buffering action for the bath. The results were almost the same as those obtained with a Watts bath under the same conditions. This result is attributed to interaction of nickel-citrate complexes at the electrode surface in the Nickel citrate bath.

Keywords
Nickel plating, Citric Acid, Nickel Citrate Bath, Watts bath, pH Buffering action

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