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Nanocomposite coatings are obtained by electrochemical deposition of silicon carbide nanoparticles (mean diameter 20 nm) in a nickel plating bath. The influence of nanoparticles on nickel electroplating is studied by electrochemical impedance spectroscopy at cathodic potential, and cathodic polarization diagrams are performed in the electrolyte with and without nanoparticles. We show that incorporation of 20 nm SiC particles into nickel deposits modifies the impedance and cathodic polarization diagrams in correlation with the modification of the surface morphology and crystallinity of the nickel matrix. © 2001 The Electrochemical Society. All rights reserved.

The aim of this work is the production and characterization of composite nickel matrix electrodeposits. Pure nickel and composite nickel matrix deposits containing either micro- or nano-particles of silicon carbide were prepared using a Watts type bath. The electrodeposition was carried out under both direct and pulse current conditions at different frequencies. With the same quantity of powder in the bath, the embedded micro-powder content is about 25-30%w while the nano-powder content is always less than 1%w. The mechanical properties of the nano-composites increases despite the low ceramic content. SEM micrographs of the microstructure and XRD-line profile analysis show that the presence of ceramic powder in both baths changes the crystallisation process leading to enhanced mechanical properties even at ceramic contents less than 1%, as in the nano-composite case. The presence of the ceramic phase and changes in the microstructure both decrease the mass loss during abrasion by up to 70% for micro-composites and 45% for nano-composites