A ball-on-disk tribometer was employed to evaluate the lubrication performance and mechanisms of innovative TiO 2 nano-additive water-based lubricants. Two experimental methods were applied to determine the optimal mass fraction of TiO 2. In the method I, lubricants were added onto the worn disk tracks at a predetermined time interval. In the method II, the disks were immersed in the lubricants continuously during the whole process of tribological tests. The results both indicate that the water-based lubricants can significantly reduce the coefficient of friction (COF). The 0.8 wt% TiO 2 lubricant demonstrates excellent tribological properties including the lowest COF and the strongest wear resistance under all lubrication conditions. The lubrication mechanisms are attributed to the rolling and mending effects of the TiO 2 nanoparticles.

No abstract

Friction and wear characteristics of TiO2 nano-additive water-based lubricant on Friction and wear characteristics of TiO2 nano-additive water-based lubricant on ferritic stainless steel ferritic stainless steel

Novel water-based nanolubricants using TiO2 nanoparticles (NPs) were synthesised by adding sodium dodecyl benzene sulfonate (SDBS) and glycerol, which exhibited excellent dispersion stability and wettability. The tribological performance of the synthesised nanolubricants was investigated using an Rtec ball-on-disk tribometer, and their application in hot steel rolling was evaluated on a 2-high Hille 100 experimental rolling mill, in comparison to those without SDBS. The water-based nanolubricant containing 4 wt% TiO2 and 0.4 wt% SDBS demonstrated superior tribological performance by decreasing coefficient of friction and ball wear up to 70.5% and 84.3%, respectively, compared to those of pure water. In addition to the lubrication effect, the suspensions also had significant effect on polishing of the work roll surface. The resultant surface improvement thus enabled the decrease in rolling force up to 8.3% under a workpiece reduction of 30% at a rolling temperature of 850 °C. The lubrication mechanisms were primarily ascribed to the formation of lubricating film and ball-bearing effect of the TiO2 NPs.

No abstract

No abstract

Hot rolling tests of a low-alloy steel were conducted at a rolling temperature of 850 • C under different lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing different concentrations of nano-TiO 2 from 1.0 to 8.0 wt%. The effects of nanolubricants on rolling force, surface roughness, thickness of oxide scale, and microstructure were systematically investigated through varying nano-TiO 2 concentrations. The results show that the application of nanolubricants can decrease the rolling force, surface roughness and oxide scale thickness of rolled steels, and refine ferrite grains. In particular, the nanolubricant containing an optimal concentration (4.0 wt%) of nano-TiO 2 demonstrates the best lubrication performance, owing to the synergistic effect of lubricating film, rolling, polishing, and mending generated by nano-TiO 2 .

No abstract