Ultrasound-assisted pulse electrodeposition and characterization of Co–W/MWCNTs nanocomposite coatings

Abstract

Co–W/MWCNTs nanocomposite coatings were synthesized by pulse electrodeposition with help of ultrasound agitation. Effect of agitation techniques of electrolyte on the microstructure and morphology of the nanocomposite coatings were evaluated. The Co–W/MWCNTs composite coating produced by mechanical agitation shows rough surface and has large and poorly dispersed CNT agglomerates in its layer and surface, resulting in this coating displaying low hardness and inferior wear resistance and friction reduction. Ultrasound agitation is much better than mechanical stirring to evenly distribute MWCNTs in the layer and surface of the composite coatings. The nanocomposite coatings produced with ultrasound agitation exhibits smoother surface, higher hardness and better tribological properties than the one produced with mechanical agitation. In addition, the ultrasonic power greatly affects the morphology and properties of the as-prepared composite coatings. As the ultrasonic power of 400 W was applied, a large number of MWCNTs are successfully incorporated and evenly distributed in the as-prepared composite coating, which result in this composite coating exhibiting the highest hardness and the best friction-reducing and anti-wear ability. In general, the differences of the friction and wear behaviors and the corresponding mechanisms of these coatings produced under different conditions are attributed to their different hardness and microstructures.