Effect of stabilizing and brightening agents and some operated conditions on electroplating kinetics of NiCu alloys from citrate-sulfate solutions

Abstract

The effect of stabilizing and brightening additives, temperature and stirring on electrodeposited kinetics of NiCu alloy has been studied by the linear polarization method. The additives almost do not affect on the electrochemical reduction rate of Cu²⁺ ions, however it has a much affect on the reduction rate of Ni²⁺ ions. The presence of boric acids, saccharin or 1,4-butynediol have increased cathode polarization, inhibited precipitation alloy and shifted discharge potential of Ni²⁺ about 100 to 150 mV towards more negative. The solution temperature strongly affected on the polarization curve over the full range of investigated electrode potential, the cathode current increased about 1.5 times when the temperature increases from 30 to 50 °C. The stirring did not increase the discharge current of Ni²⁺ ions, on the contrary, it significantly increased the discharge current of Cu²⁺ ions, increasing from 2 to 3 times compared to when did not stir.