Research On Lubricating Performance Of Nanoparticle Additive And Tribological Simulation

Nano friction-reducing&self-repairing additive, carried by lubricant, was involved in the physicochemical changes of the friction contact surface, formed the tribo-film which was dense and smooth, can effectively improve the wear resistance and surface condition because of the higher mechanical property of the film, reduced the friction and wear. The tribological performance of Nano friction-reducing&self-repairing additive combining with friction mod ifier(molybdenum dialkyldithiocarbamate MoDTC), detergent dispersant(overbased liner alkyl benzene synthetic calcium sulfonate T106) and base oil(Poly alpha olefin PAO4) was evaluated using a reciprocating friction and wear tester MFT-4000. The morphologies of the worn surface and its chemical composition were investigated using a scanning electron microscope and an energy dispersive spectrometer. The active mechanism of the additives was discussed and the contact stress of the surface was analyzed using finite element software. The main results are concluded as follows.1. It can effectively improve the tribological properties o f the base oil when added the Nanoparticle additive into the oil; the friction coefficient changed inconspicuously, but the antiwear performance increased after added different proportions of Nano additive compounded with T106into oil; when2percent of Nano additive combining with MoDTC were added in the base oil, antifriction properties of the mixed system was improved and the wear resistance decreased slightly; when the optimal concentration ratios of Nanoparticle additive, MoDTC and T106was realized in the base oil, friction coefficient was decreased and the antiwear performance increased obviously, the lubricant had the best tribological properties.2. When PAO4+0.5%Nano+0.5%MoDTC+5%T106was composited in lubrication, the results showed that the wear scar was the smallest and the wear surface was smooth and dense, using the scanning electron microscope; compared to the base oil, C, O element content of the composited oil increased and Fe content decreased, also detected Ca, S elements using energy dispersive spectrometer. It proved that the protective films formed on the friction interface were good to enhance anti-wear and reducing-friction properties.3. The surface stress ideal model of the ball on disc was analyzed using the finite element software ANSYS. The simulation result showed that the pressure were not equally distributed on the contact surface, which leaded to the damage of the material in the worn edge easily.