Morphological insights associated to instantaneous nucleation and growth in Cr(III) electrodeposition on nickel in aqueous media

Abstract

In this work, experimental evidence of instantaneous nucleation and growth transients were observed for Cr(0) electrodeposits in aqueous electrolytes, using Cr(III) as precursor species in a double potential step process. This progression occurs via a Cr(II) intermediate, which should be stabilized in aqueous media to afford its proper reduction. This mechanism is rarely observed in aqueous media due to rapid onset of hydrogen evolution and adsorption due to both the acidity and chemical composition of the electrolytic medium employed. Using this approach to prepare a potentiostatically controlled electrodeposit, afforded functional coating on a substrate which is employed for industrial applications (Ni). The morphological features observed from microscopic analysis of the surfaces allowed considering that such instantaneously formed nuclei are important in determining the grain size of the final coating and as such could be controlled in a more significant way with this potentiostatic technique, providing an alternative to the galvanostatic classic approach.

Keywords

• Cr(III) aqueous electrodeposition
• 2D nucleation
• Double step potential chronoamperometry
• Surface morphology
• Coating thickness