Lubrication property of multi-layer sintering material under hydrodynamic lubrication

In order to solve the problem that the hydrodynamic oil film formed during the work process of sintering materials is easy to seepage into porous medium which leads to the degradation of lubrication property, multi-layer sintered materials with different porosity structures were prepared by powder metallurgical technique to achieve the unification of high load capacity and good lubricating property. Fluid lubrication model of the multi-layer sintered materials in polar coordinates was established based on Darcy's law firstly, numerical simulation were conducted by using the finite difference method, and the effects of surface Darcy flow on the lubrication property of oil film under different rotate speeds were investigated. Then, the end face friction experiment were conducted under oil lubrication to verify the simulation results. The results show that the oil film lubrication property of the multi-layer sintered materials is much more better than that of the ordinary monolayer sintered materials. With the decrease of the surface porosity, the lubrication property of the multi-layer sintered materials becomes better in the given range of the porosity. The oil film lubrication property of multi-layer sintered materials is improved relatively when considering the surface Darcy flow, and the improving effect becoming obvious gradually with the rotate speed increases. There is a good agreement between the conclusions obtained by friction test and numerical analysis. The research work can provide theoretical bases for tribological property analysis and structure design of the multi-layer sintered material at some degree.