Ultrasound-assisted electrodeposition of thin nickel-based composite coatings with lubricant particles

Thin Ni composite coatings with hBN and WS₂ particles were ultrasonically-electrodeposited on Cu with no need of a surfactant. Although the combination of mechanical agitation and ultrasound yielded the best dispersions, ultrasound on its own during plating yielded coatings with a more uniform distribution of particles. Ni/hBN and Ni/WS₂ composite coatings electrodeposited under ultrasound were characterised by different methods: GD-OES to estimate particle content, XRD to analyse the preferred orientation, FIB-SEM to analyse the surface morphology and microstructure, and microhardness tests to measure the hardness. Whereas Ni/hBN composite coatings showed little difference compared to pure Ni deposits, the incorporation of WS₂ into Ni had a significant effect on the preferred orientation, the surface morphology and the grain size of the coatings, refining the Ni crystal down to the nano-scale. The latter had a significant effect in the hardness of the coatings, despite the 'soft' nature of the WS₂ particles.