Composition and structure of Ni-Co coating depending on the ratio of Ni and Co in a citrate electrolyte (original) (raw)

This paper reports the effect of the Ni/Co ratio in a citrate electrolyte (with an optimum content of Na3 citrate) on the deposition kinetics, chemical and phase composition of the Ni-Co alloy coating, current cathodic efficiency of the electrodeposition, and morphology of the coating. It was established that by increasing the Co content in the solution, the deposition potentials of the Ni-Co alloy were shifted towards the values where Co reaches a plateau of limited diffusion current. When the Co content in the solution increases and the applied cathodic potential gets more positive values, the Co content in the alloy increases (up to max 85%), and so does the cathodic current efficiency (in respect to electrodeposition of the alloy). The Co content in the alloys deposited in all studied electrolytes was over 60 mass % and the phenomenon of "anomalous" co-deposition of Ni and Co in the alloys was identified. The SЕМ images of the alloy coatings deposited at potentiostatic...