Nickel electrocrystallization in different electrolytes: An in-process and post synthesis analysis

Abstract

The present report is solicited for contributions of nucleation–growth mechanisms of electrodeposition of nickel in different aqueous solutions. The cyclic voltammetry (CV) analysis has been performed on electrocrystallized Ni to understand the deposition and dissolution processes in four types of baths i.e. sulphate, chloride, Watts and sulphamate baths. The result shows that for chloride and sulphate bath there are distinct peaks but for Watts and sulphamate there is no such cathodic peaks, rather it increased to the specified vertex potential. And also it is observed that for sulphate bath the dissolution peak is observed but the physical observation of the electrode after the completion of CV depicts that dissolution takes place partially. The in-process and post synthesis analysis was studied by electrochemical techniques followed by morphological studies (by scanning electron microscope (SEM) and atomic force microscope (AFM)). The other technique used in this study includes XRD to analyze the phase, crystallite size and lattice strain, surface profilometer and Nanoindenter to analyze the structure and properties of deposits (residual stress and hardness). The thickness of the film varies from 1.3 to 2.7μm for baths from sulphate, sulphamate, Watts to chloride baths. The compressive stress obtained for different baths vary from 4.015 to 11.231GPa and tensile stress vary from 3.778 to 16.608GPa from sulphamate, Watts, sulphate to chloride baths. Also the stress reduces and hardness increases from sulphamate, Watts, sulphate to chloride baths. The grain size decreases and lattice strain increases from sulphamate, Watts, sulphate to chloride baths.