Effect Of Carbon Nanomaterials On Vacuum Super Lubrication Properties Of H-DLC Films

Diamond like carbon(DLC)film is a three-dimensional network structure composed of diamond structure and graphite structure,which is usually amorphous or amorphous nanocrystalline composite structure.Because of its excellent properties such as high hardness,low friction,low wear and corrosion resistance,it has a wide application prospect in aerospace field.However,for space moving parts,DLC film has some limitations,such as poor wear-resistant life,inconvenient traditional fluid lubrication and so on.Carbon nanomaterials have the advantages of low friction,low cost,no pollution and so on.Therefore,this paper simulates the space environment,uses the rotary friction testing machine,through changing the types of carbon nanomaterials and graphene content,explores the friction reduction and anti-wear mechanism of carbon nanomaterials on diamond-like carbon films,and then regulates the super lubrication life of diamond-like carbon films.The results show that:(1)In vacuum environment,carbon nanomaterials can significantly reduce the friction and wear of DLC films.However,due to the different types of carbon nano materials,there are obvious differences in lubrication effect.The lubrication effect of carbon nanotubes is the worst,and the friction and wear of diamond-like carbon films do not decrease significantly;Nano diamond and onion carbon have better lubrication effect,the friction coefficient of the film is significantly reduced,and the wear rate is reduced by an order of magnitude.The results show that graphene has the best antifriction and antiwear effect,and the film is in the super lubrication state during the whole friction process,and the wear rate of the film is reduced by two orders of magnitude.It is speculated that the reason is that graphene is adsorbed between the friction interfaces due to Van Der Waals Force in the friction process,which has a good lubrication effect on the film.(2)In vacuum environment,graphene has the best lubrication effect on DLC films.When the concentration of graphene changes,the tribological properties of DLC films are greatly different.When the graphene concentration is 50 mg / L and 200 mg / L,the friction and wear of the films do not decrease significantly;When the concentration of graphene is 150 mg / L,the friction coefficient decreases significantly and the wear rate of the film decreases by an order of magnitude;When the concentration of graphene is 100 mg / L,the friction coefficient is always in the state of super lubrication,and the wear rate of the film decreases by two orders of magnitude.It is found that with the increase of graphene concentration,the friction coefficient and wear rate of the films decrease first and then increase.In order to further explore the anti-wear mechanism of carbon nano materials and graphene concentration on diamond-like carbon(DLC)films,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Raman spectroscopy(Raman)and other instruments were used to analyze and characterize the wear marks and ball milling spots of DLC films.