Frictional and wear properties of cobalt/multiwalled carbon nanotube composite films formed by electrodeposition

Carbon nanotubes (CNTs) have solid lubricity due to their unique structure, and as such, CNT composites are also expected to exhibit superior tribological properties. In this study, Co/CNT composite films were fabricated using a composite electrodeposition technique, and their tribological properties were investigated. Three different sizes of multiwalled carbon nanotubes (MWCNTs) were used as the CNTs in this study. The microstructures of the composite films were examined using scanning electron microscopy. Frictional and wear properties were examined using a ball-on-disk method without any lubricants at room temperature and at high temperatures (100-500 °C). The Co/MWCNT composite films had lower coefficients of friction than a cobalt film at room temperature. In contrast, the coefficients of friction of the Co/MWCNT composite film at high temperature became higher than that at room temperature and slightly lower than that of a cobalt film. These results are likely related to the formation of cobalt oxides on the surface and the heat dissipation of the MWCNTs.