ANALYSIS ON THE PRODUCTION PROCESS AND THE ELECTROREDUCTION PROCESS OF THE DOUBLE METAL HYDROXIDE AS A PRECURSOR OF ALLOY PLATING

在硫酸盐浴电沉积Zn-Ni合金时，低品位Zn优先沉积，而高品位Ni优先沉积。这种行为被归类为“异常共沉积”。根据阴极产氢量和pH值的增加，认为锌镍的异常共沉积是由于氢氧化锌在阴极上的优先沉淀和镍沉积的抑制所致。而当Zn^<2+>和Ni^<2+>同时存在时，析出的不是氢氧化锌，而是两种金属的双氢氧化锌。本文阐明了含Zn^<2+>和Ni^<2+>的镀液中产生的双氢氧化物的作用。研究了双氢氧化物的生产工艺及氢氧化物的电还原

In the electrodeposition of Zn-Ni alloy from sulfate bath, less noble Zn preferentially deposits compared to noble Ni. This behavior is classified as "anomalous codeposition". It has been considered that the anomalous codeposition of Zn-Ni is 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, in the case that both Zn^<2+> and Ni^<2+> coexist in the solution, not the zinc hydroxide but the double hydroxide of both metal precipitates. In this paper, the role of the double hydroxide from the plating bath containing Zn^<2+> and Ni^<2+> has been clarified. The double hydroxide production process and the electroreduction of the hydroxide were investigated