Experimental analysis on tribological properties and lubricating mechanisms of oil-based Al₂O₃ nanofluids applied on steel-brass frictional pairs

Abstract

The present research studied the tribological properties of Al2O3 nanofluids applied on steel-brass contacts. It was found that the coefficient of friction could be stabilized and reduced by approximately 40.7% after adding Al2O3 nanoparticles. The wear width and wear depth could be reduced by up to 39.6% and 69.3% while using 1 wt% Al2O3 nanofluid. By examining the worn surfaces, Al2O3 nanoparticles were embedded into brass by external load to form a hard case, which could protect the brass surfaces from wear loss. In addition, some black spots with low shear resistance containing high carbon content were formed which were the result of the presence of oleic acid. In summary, the excellent lubricating performance of Al2O3 nanofluids was mainly associated with the physical embedment of Al2O3 nanoparticles and tribo-films of oleic acid. The results obtained in this research can be used to enhance the performance and extend the service life of some engineering components such as journal bearings with inner brass bushings.

Tribological properties of Al2O3/WS2 oil-based composite lubricant utilized on steel-brass frictional couples

“…The optimal concentration was about 0.01 wt%. Yang et al [20] prepared oil-based Al 2 O 3 nanofluids with various concentrations of 0.2 wt%, 1 wt% and 3 wt%. It was found that the positive effects of Al 2 O 3 nanofluids on frictional force were not dependent on the concentrations.…”