A new method for surface modification of TiO2/Al2O3 nanocomposites with enhanced anti-friction properties

In this paper, the TiO2/Al2O3 composite nanoparticles were prepared by a hydrothermal method and in situ modified with acrylic acid. It was found that the mean particle size of modified TiO2/Al2O3 composite nanoparticles was about 80 nm with a uniform distribution by the particle size analysis. The modified TiO2/Al2O3 composite nanoparticles can disperse in lubricating oil homogenously for several weeks. The dispersion stabilization of modified TiO2/Al2O3 composite nanoparticles in lubricating oil was significantly improved in comparison with the as-prepared nanoparticles, which was due to the introduction of grafted polymers by surface modification. The formation of covalent bands was identified by Fourier transform infrared spectrum. Under an optimized concentration of 0.1 wt%, the averaged friction coefficient was reduced by 14.75%, when the modified TiO2/Al2O3 composite nanoparticles were used as lubricating oil additivities.

► The preparation and modification of nanoparticles were finished by an in situ hydrothermal method.
► By surface modification, TiO2/Al2O3 composite nanoparticles can disperse in mineral oil homogenously.
► The modified TiO2/Al2O3 nanoparticles as lubricating oil additives can greatly reduce the friction coefficient.