Effect of tetraborate ions on electrodeposition of nickel—copper alloy from a pyrophosphate bath

✍ Scribed by Masami Ishikawa; Hidehiko Enomoto; Masao Matsuoka; Chiaki Iwakura

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 409 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)e0169-z

✦ Synopsis

Effect

of tetraborate ions on NiCu alloy electrodeposited from a pyrophosphate bath has been studied. Deposits from a tetraborate-free bath were non-uniform, blackish and contaminated with insoluble compounds, which was confirmed to be nickel hydroxide hydrate by X-ray diffraction and X-ray photoelectron spectroscopic analysis. In contrast, the deposits from a bath containing sodium tetraborate were smooth, fine-grained, nickel-rich and gave nickel-like lustrous appearance. Sodium tetraborate was found to improve the quality of Ni-Cu alloy deposits by preventing the increase of pH at electrode/electrolyte interface and the precipitation of the insoluble nickel hydroxides.