Study On Mechanical And Frictional Properties Of Solid Lubrication Film Silver

With the advancement of science and technology,solid lubrication film,as one of the main forms of lubricant,is widely used in aerospace and civil machinery because of its excellent friction and wear characteristics.It is great significance to study the mechanical properties and friction properties of lubricating film at nanometer scale,which is helpful to improve the lubrication performance of lubricating film and prolong the working time of lubricating film.The solid lubricating film Ag has good stability,strong reflection,good electrical conductivity,and it is widely used in aerospace precision instruments.In this paper,through buliding the composite model of Cu based Ag film,studied and analyzed the model’s friction law and mechanical properties.Firstly,the composite model of Cu based Ag film is established by using the molecular dynamics software Lammps.Obtaining the lattice constant’schange,model volume’s change and radial distribution function in the system relaxation process verifies the stability and correctness of the model.Secondly,in order to study the composite model’s microscopic friction law under different working conditions,the sliding friction process of diamond rough peak in the plane of Cu based Ag film composite model was simulated by molecular dynamics method.And the effect of the velocity,temperature and engraving depth on friction were discussed.In order to study the microscopic mechanical properties of the composite model,the nano-indentation process of the model was simulated by bridge domain multi-scale coupling method.The load-displacement curve was analyzed,and the nano-hardness and elastic modulus of the composite model were calculated.Finally,the macroscopic friction experiments of Cu based Ag film specimens are carried out by means of surface performance measuring instrument,and the microscopic results simulated by Lammps and the macroscopic friction experimental results are compared and analyzed.It is found that the influence of velocity on the friction coefficient of the composite body is the same under the two scales.The nano-indentation experimentof Cu based Ag film specimens was carried out by using nano-indentation instrument.It was found that the multi-scale simulation was in good agreement with the numerical results obtained by nano-indentation experiment.