Pyrimidine derivative-based cyanide-free silver electroplating bath

ABSTRACT

Prior investigations have implemented pyrimidine-derivative, 2,4-pyrimidinedione (Uracil), as a complexing agent in cyanide-free silver plating and achieved good adherent and ductile silver deposits on copper- and nickel-coated copper substrates. In this research, pyrimidine-derivatives, 2,4-pyrimidinedione (Uracil) and 5-methylUracil (Thymine), were used as complexing agents to develop a cyanide-free process for silver deposition on copper substrates. It has been discovered that when 2,4-pyrimidinedione (Uracil) or 5-methyluracil (Thymine) was added into a 5,5-dimethylhydantoin (DMH)-based cyanide-free silver plating solution; a semi-bright silver film was deposited on copper substrates. Moreover, a high current efficiency value compared to that of cyanide-type silver solution could be achieved using a cyanide-free silver solution with a DMH and Uracil formulation. The brightness and surface morphology of silver deposits obtained from DMH and Uracil formulation with the addition of polyethyleneimine (PEI) were evaluated.

KEYWORDS:

• Silver
• cyanide-free
• electroplating
• 5,5’-dimethylhydantoin
• pyrimidine derivative
• uracil
• thymine

Acknowledgements

This work was presented at the INTERFINISH2020, 20th World Congress, held online via Zoom during 6–8 September 2021.

Disclosure statement

No potential conflict of interest was reported by the author(s).