Effect of Growth Parameters on the Microstructure and Morphology of Electrodeposited Ni Films

Abstract

Electrodeposition is a versatile and cost-effective method to produce polycrystalline metallic films with wide-ranging applications. Electrodeposited polycrystalline nickel (Ni) thin films are widely used in technological applications due to their favourable mechanical, electrical, and chemical properties. The performance of these films is strongly influenced by their surface morphology and microstructure, which are governed by growth parameters such as deposition potential, electrolyte composition, film thickness, and the presence of additives. In this work, the evolution of morphology and microstructure in electrodeposited Ni films was systematically investigated, with particular emphasis on the role of chloride ions in the electrolyte. Ni thin films were electrodeposited under controlled conditions and characterised using a combination of surface and diffraction-based techniques, including Atomic Force Microscopy (AFM), High-Speed AFM (HS-AFM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Electron Backscatter Diffraction (EBSD), and Focused Ion Beam (FIB) analysis. AFM data were analysed quantitatively using scaling and slope analysis to describe surface roughness and local grain slope. Grain area analysis revealed that increasing film thickness led to larger grains, with films deposited in the presence of chloride ions exhibiting significantly larger grain areas and higher local slopes. XRD and EBSD analyses demonstrated a clear evolution of crystallographic texture with increasing thickness, showing a transition from Ni(111) to a dominant orientation. This transition was more pronounced in chloride-containing films. Cross-sectional FIB–EBSD analysis further revealed that -oriented grains grew preferentially in a columnar manner, overgrowing neighbouring grains and leading to a strong fibre texture. In a chloride ion-containing electrolyte, columnar grain growth was established at an early stage of growth compared to films prepared without chloride ions. This resulted in a larger grain area and a higher local slope for films prepared in a chloride-containing solution. The presence of chloride ions was found to modify grain growth behaviour, likely through adsorption-mediated effects that stabilise step edges and enhance surface diffusion. 3D EBSD data revealed that this behaviour was consistent throughout the film thickness. In-situ HS-AFM real-time observation of the grain growth rate was attempted to gain insight into local grain growth behaviour. Grain growth rates were also calculated at different later growth levels from successive HS-AFM scans, providing preliminary findings that grains with higher topography generally grew faster, except for a few regions where recessed grains exhibited overgrowth. The effects of AFM tip condition and FIB milling parameters on grain growth and quantitative analysis are also discussed. At the same time, correlative analysis between HS-AFM and EBSD enabled direct comparison of grain area distributions from the same region. Overall, this study establishes quantitative links between growth conditions, surface morphology, and microstructural evolution in electrodeposited Ni films, providing an improved understanding of chloride-assisted texture development and grain growth mechanisms.

Date of Award	26 Feb 2026
Original language	English
Awarding Institution	University of Bristol
Supervisor	Walther Schwarzacher (Supervisor) & Tomas L Martin (Supervisor)