Study of the effect of Ammonium Chloride on the Nanostructure of Hierarchical Nickel Coatings Created by Electroplating Process: the Microstructure and Simulation Studies

The effect of the addition of ammonium chloride crystalline modifier to nickel electroplated coating method with thickness of 4/8 μm. Field Emission Scanning Electron Microscope (FESEM), X-ray diffraction (XRD) and Atomic force microscopy (AFM) were used to investigate the microstructures and morphology and atomic simulations based on Density Functional Theory (DFT), Monte Carlo and Molecular Dynamic (MD) were used to study the adsorption and desorption behavior and growth of the nickel layer on copper substrate. Microstructural and Monte Carlo simulation results showed that the dislocation steps are the preferred adsorption sites of complex, which causes the formation of hierarchical nickel coatings. Molecular dynamics simulation was used to investigate the complex adsorption mechanism in the presence of nickel ion. It was found that in the presence of crystalline modifiers, the complex absorbs faster than nickel ions on the nanocones and they stop growing layer along with the cones. Also, the addition of ammonium chloride to the plating bath transforms the structure from microconical to hierarchical and petal with the formation of nickel ammonium complex. This was confirmed by atomic simulations and structural analyzes and was in full compliance with the metal ion deficient layer (MIDL) theory.