Effect of NH4+ and Co++ Ions on the Hardening of Electrodeposited Nickel from Nickel Acetate in Amide Solvents

• Published in: Transactions of the Japan Institute of Metals 1987, Vol.28(11), pp.916-924
• Main Authors: Srivastava, H. K., Tikoo, P. K.
• Format: Article
• Language: English
• Subjects: ammonium ion; Applied sciences; cobalt ion; Cross-disciplinary physics: materials science; rheology; electrodeposition; Exact sciences and technology; hardness of deposits; Materials science; Metallic coatings; Metals, semimetals and alloys; Metals. Metallurgy; non-aqueous baths; Physics; Production techniques; Specific materials; Surface treatment
• ISSN: 0021-4434; 2432-4701
• DOI: 10.2320/matertrans1960.28.916

Addition of 0.2 kmol/m3 ammonium acetate, along with 0.1 kmol/m3 boric acid, to nickel acetate/formamide, nickel acetate/N-methylformamide and nickel acetate/N, N-dimethylformamide baths resulted in nickel electrodeposits having a high degree of hardness. Further, the addition of a small amount of cobalt acetate was found to be highly effective in enhancing the hardness as well as improving the surface appearance of nickel deposits. The presence of ammonium and cobalt ions was highly influential in improving the hardness. Nevertheless, the basicity and dielectrical properties of amide solvents were highly instrumental in deciding the grain refinement of electrodeposited nickel. Peeling due to the internal stress of the electroplates obtained from a nickel acetate/formamide bath disappeared totally when they were annealed at 473 K. Scanning electron micrography revealed refinement in grain size with successive inclusion of methyl group in formamide.