Manufacture And Characterization Of Oleophobic Surface Of 9Cr18 Bearing Steel

As the major component of spacecraft attitude control system,the momentum wheel has a crucial impact on the accuracy,life and reliability of the spacecraft,and the longlife stability of bearing's friction moment plays an important role in the accuracy.At present,the bearing lubrication system of the long-life momentum wheel uses the porous oil reservoir release microscale oil and transport it to the contact area slowly to guarantee long-time use.However,the creeping and evaporation loss of the oil during the conveying process causes the bearing lubrication to fail before the design life and the increasement in friction torque.While,low adhesion and easy rolling characteristics of oleophobic surface can reduce creeping loss to support a stable supply.Therefore,this thesis carry out three parts work,which contains wettability simulation modle and optimization method based on Cellular Potts Model(CPM);wettability simulation of 9Cr18 with real and simulated roughness surfaces;manufaction and wettability test of oleophobic 9Cr18 surface.The design parameters of the surface with low adhesion are proposed by study with wettability theory and modification study,which provides theoretical and experimental guidance to the decreasement of creeping loss of the lubricating oil no the bearing chamber and extension of the momentum wheel serve-life.After build the simulation model of wettability based on CPM,the influences of simulation parameters are discussed and verifies the validity of the model on different wettability surfaces.The single-valued and multi-valued minimum energy method is proposed to improve the accuracy of the simulation results.The above works provide a basis for lubrication oil wettability on 9Cr18 textured surface simulation.After build the rough surface wettability simulation model,this thesis establish the wettability simulation software based on CPM.It use real surface and experiment verify the effectiveness of this model.Based on the model above,this thesis used twodimensional digital filtering method produces rough surface and propose the design parameters of low adhension surface,which provides indication of wettability modification.A wettability functional surface composite processing method based on femtosecond laser processing-HCl chemical etching-perfluorodecyltrimethoxysilane decration is established.The machining parameters' influences on 9Cr18's wettability is discussed.Oleophobic 9Cr18 surface with contact angle of 128° and a minimum roll-off angle of 40° is established.The test results show that this method can be used on low adhension Oleophobic surface manufaction.In this thesis,three parts of studies are carried out,including 9Cr18 planar and periodically grooved surface wettability simulation and optimization,real and simulated rough surface wettability simulation,and composite processing of 9Cr18 steel oleophobic surface.It provides guidance for the design and processing of the oleophobic surface with wettability simulation,mechanism study and test processing,which can decrease the creeping lose of oil and are the basement for the improvement of the stability transport of the momentum wheel bearing.