Microstructure and mechanical properties of electrodeposited Ni and Ni-matrix-nanocomposite thin films

Ni and Ni-matrix-nanocomposite thin films were produced by constant-current electrodeposition from a sulphamate bath. The composite consisted of an array of Ag-coated SnO2 nanowires grown onto a substrate, around which the Ni matrix was deposited. The hardness and Young's modulus of the films were studied by microindentation, showing a strengthening of 66% for the composite with respect to Ni films produced using the exact same bath and deposition parameters as the composite's matrix. A straightforward method for evaluating the stress-strain relationship from indentation data based on analytical and computational models available in the literature was proposed and evaluated. A thorough microstructure characterisation by scanning electron microscopy together with electron backscatter diffraction was conducted to assist in the interpretation of the mechanical response of the films. The Ag-SnO2 in the composite prevented the development of texture and was responsible for a grain size reduction of 85%.