Tribological properties of water-based nanofluids prepared by multi-walled carbon nanotubes composites filled with sulfurised isobutylene

Sulfurised isobutylene (T321) was filled into the cavity of multi-walled carbon nanotubes (MWCNTs) in order to synthesise MWCNT/T321 composites. Tribological properties of water-based nanofluids with composites as additives were systematically investigated using a four-ball configuration. The results showed that MWCNTs were filled by T321 with a filling rate of 22.5%. The nanofluids prepared by the composites produced a significantly lower coefficient of friction and wear loss, in comparison with the lubricants containing only MWCNTs or T321. Such improvement was attributed to the fact that during sliding the T321 filled into composites was released onto the rubbing surface to generate a lubricating film, resulting in a low resistance to shear, whilst the MWCNTs served as nano-bearings on the formed lubricating film.