亜鉛-ニッケル合金めっき浴からの共沈物の電解還元

抄録

With electrodeposition of Zn-Ni alloy from a sulfate bath, less noble Zn preferentially deposits compared to noble Ni. This behavior is classified as “anomalous codeposition.” The anomalous codeposition of Zn-Ni may be due to the preferential precipitation of zinc hydroxide on the cathode and the inhibition of nickel deposition according to the hydrogen production at the cathode and the pH increase. However, when both Zn²⁺ and Ni²⁺ coexist in the solution, the zinc hydroxide does not precipitate while the double hydroxide of both metals does. In this paper, the role of the double hydroxide obtained from a plating bath containing Zn²⁺ and Ni²⁺ has been clarified. The double hydroxide production process and the electroreduction of the hydroxide have been investigated.