Study On Tribological Behavior Of Sb Nanopowders As Additive In Liquid Paraffin

Antimony (Sb) nanopowders were prepared by electrochemical method and their dispersion and stability in the pure liquid paraffin (LP) was inspected. The tribological properties of lubricant with Sb nanopowders were studied on the friction and wear testing machine. The lubrication mechanism was also discussed. The main conclusions were reached as followed.1. Sb nanoparticles with different morphology and size were prepared by electrochemical method, while the surface was modified by using OP-10. The morphology, size and coating effects of the Sb nanoparticles were analyzed by TEM, XRD and FTIR. The results showed that time effects and current effects existed when Sb nanoparticles were synthesized. With reaction time increasing, the size of Sb nanoparticle became larger and Sb nanoparticles agglomerated. When the current density changed within a certain range, the higher current density was conducive to the formation of Sb nanoparticles. The surface modification of Sb nanoparticles was obtained mainly by coating of OP-10 through chemical adsorption between OP-10 long-chain molecular structure and Sb nanoparticle, and interaction of hydrogen bond and Van der Waals force among OP-10 long-chain alkyl molecular, while the bond of ether also played a key role during the reaction. The dispersion and stability of Sb nanoparticles in the pure LP related to their additive amount, and the optimum amount was 0.5%.2. The tribological properties of Sb nanopowders as additives in LP were evaluated compared with these of pure LP on a four-ball test machine. The results showed that under lubrication of LP added with Sb nanopowders, it displaied the poor frictional properties at a lower load, even when in the lubrication of LP with higher additive amount of Sb nanopowders, its frictional properties showed deterioration, but it represented the excellent frictional properties at higher loads; when the Sb nanopowder addition level was 0.1%, the synthetic performance with friction reducing (FR) and anti-wear (AW) was the best. The research showed that friction coefficient which was in lubrication with LP adding Sb nanopowder was affect less than that in pure LP lubrication by the load.3. The morphology and chemical composition of worn-out surface were investigated by SEM and EDS, and the lubrication mechanism of Sb nanopowder was also discussed. Under a lower load, pure LP instead of Sb nanopowder played a main lubrication role; but under a higher load, Sb nanopowder showed excellent anti-wear and friction reducing effect and the wear surface represented the self-healing phenomenon in the extension of friction time. The study showed that Sb nanopowder generated lubricating film in the friction surface during the friction process. The function of osmosis didn't occur fully between Sb nanopowder and the friction pair, and Sb nanopowder had not play its lubricating properties fully under lower load; the function of osmosis occurred between Sb nanopowder and the friction pair, a layer of chemical reaction film was forming and Sb nanopowder exhibited the excellent anti-wear and antifriction properties under higher load due to the doublelayer lattice structure of Sb.