Pyrimidine derivative-based cyanide-free silver electroplating bath

Abstract

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.