Preparation and Tribological Properties of Water-Based CNTs/MoS₂ Composite Nanofluid

The ionic liquid EMImBF₄ was used to disperse multi-walled carbon nanotubes (MWCNTs), and EMImBF₄-Gum Arabic (GA) was used as an additive to disperse molybdenum disulfide (MoS₂). The two aqueous solutions were mixed to obtain a composite nanofluid. Raman spectroscopy was used to analyze the degree of modification of MWCNTs, and the dispersion and suspension stability of the composite nanofluid were characterized by absorbance and particle size. The wetting and tribological properties of the composite nanofluids with different nanoparticle ratios were measured. The results showed that for the mass fractions of MWCNTs of 0.6% and MoS₂ of 1.2%, the fluid had the best spreading and film forming ability. Its contact angle was about 63.04°, which was 23.55% lower than deionized water. In addition, the anti-wear performance was the best. In specific the average friction coefficient was 0.073, which was 61.98% lower than deionized water, and the volume wear rate was reduced by 67.87%. The wear scar was shallow and the surface was smooth without furrows. X-ray photoelectron spectroscopy showed that MWCNTs and MoS₂ engaged in friction and produced a film on the substrate, thereby synergistically achieving high-efficiency lubrication.