D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia

E. V. Lopukhova, Undergraduate Student at the Department of Innovative Materials and Corrosion Protection, e-mail: lopoohova18@gmail.com
K. N. Smirnov, Associate Professor at the Department of Innovative Materials and Corrosion Protection, Candidate of Technical Sciences, e-mail: smirnov.k.n@muctr.ru
D. V. Mazurova, Associate Professor at the Department of Innovative Materials and Corrosion Protection, Candidate of Technical Sciences, e-mail: mazurova.d.v@muctr.ru
T. A. Vagramyan, Head of the Department of Innovative Materials and Corrosion Protection, Doctor of Technical Sciences, Professor, e-mail: vagramian.t.a@muctr.ru

An increasing number of devices that use printed circuit boards emphasizes the need to develop more efficient, cost-effective and reliable techniques for surface finishing of printed circuit boards. Immersion coatings are used as the top coat designed to protect conductor paths of printed circuit boards from oxidation and enable the soldering process. Due to its proneness to fast passivation, nickel is poorly solder weldable. Gold is known to protect this metal from oxidation. It dissolves in solder providing good flowability and hence solderability. Immersion gold is the most popular technique when it comes to manufacturing critical components as it ensures a combination of good solderability and surface flatness for mounting and soldering highly integrated components, which is a pre-requisite for modern items, with an increasing density of printed boards. Of acute importance today is the problem of developing an in-country immersion gold solution that could fully substitute all similar products made abroad. This paper looks at the immersion gold plating solution that contains potassium dicyanoaurate, a chelate-type ligand, a reducing agent and a buffering additive. The aim of this research is to understand how the immersion goldplating conditions influence the gold plating thickness and what would be the optimum parameters under which the deposited layer would meet the IPС-4552 standard. It was established that the introduction of the reducing agent to the immersion gold plating solution influences the plating thickness, with the process duration being rather long, and thus helps maintain the thickness of the finish while the concentration of gold in the solution drops. The paper demonstrates that the immersion gold plating solution can work in a stable mode for quite a long time.

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