Experimental investigation of the effect of IF-WS2 as an additive in castor oil on tribological property

Abstract The development of eco-friendly lubricant is the requirement of the times. In this paper, the modified IF-WS2 nanoparticles are added to castor oil as additives to prepare mixed lubricant. The lubrication performances of the mixed oil are investigated by ball-on-disc rotary friction tester, and then the surface scratches are characterized by depth of field digital microscope, scanning electron microscope and Raman spectrometer. Experiments reveal that compared with the base oil, the friction coefficient and worn volume decrease by 27.4% and 47.2% after adding modified IF-WS2 as additives under 300 rpm and 5 N conditions, respectively. From mechanism analysis, this improvement in lubrication performance is attributed to the polarity of castor oil and the unique pressure bearing structure and dispersion stability of modified IF-WS2, which makes that the castor oil molecules can better adsorb around the modified IF-WS2 to form heavy loading bearing friction oil film so as to reduce friction and wear. In summary, results indicate the mixture of modified IF-WS2 nanoparticles and vegetable lubricating oil has an attractive prospect in the field of environmentally-friendly products.