Effect of Particle Size on Dispersibility of Antimony Nanoparticles in Lubricating Oil

Antimony nanoparticles, whose surfaces were modified by alkylphenol polyoxyethylene ether, with various particle sizes were prepared by electrochemical method. The dispersibility of antimony nanoparticles in 32# engine oil was characterized by means of steady-state sedimentation experiment and spectrophotometric method when the resulting antimony nanoparticles with various particle sizes were dispersed in lubricating oil with 0.5% of mass fraction. The results show that the particle size of antimony nanoparticle has significant effect on its dispersibility in lubricating oil. When the mass fraction of antimony nanoparticles in lubricating oil is 0.5%, the steric hindrance effect of surface adsorption layer coating on particles surface increases with decreasing of particle size. Meanwhile, the aggregating probability decreases among nanoparticles under the action of the collision generated by Brownian motion. As a result, the sedimentation velocity of nanoparticles in lubricating oil becomes slower and the dispersion stability of antimony nanoparticles in lubricating oil becomes better.