| Due to the development of modern science and technology,the negative effects caused by friction become more and more serious.Not only the destruction and loss of the materials caused by friction,but also the waste of energy and pollutant emissions caused by friction are very serious problems.With the development of science and technology,the field that mankind can stand by was greatly expanded.Similarly,there are more stringent requirements on the long life and high reliability of moving parts and institutions,and the development of new technologies has enabled people to make the exploration of micro and macro scales by leaps and bounds.In general,one of the key technologies to significantly improve life and reliability of the service of moving parts is the excellent lubrication technology.The lubrication of solid films has the advantages of wide operating temperature range and simple structure,such as diamond-like carbon film,which has gained more applications in micro/nano mechanical systems,industrial machinery parts,biological instruments,optical instruments and aerospace fields.In particular,during the research of diamond-like carbon films,tribologists discovered an amorphous carbon film with unique nanostructures,ie,fullerene-like nanostructures embedded in an amorphous carbon network.It has higher hardness and elastic recovery,chemical inertness and friction and wear characteristics than conventional amorphous carbon films.In particular,hydrogenated fullerene-like carbon films have more excellent tribological properties due to the presence of hydrogen.However,for the solid lubricating film,the disadvantages such as the limited life,the difficulty of replacement and easy oxidation and degeneration limit its further application.Therefore,it is the urgent need for solving the problem to improve the life and reliability of moving parts.Based on the above problems,on the one hand,this paper studies the life span and reliability of moving parts by investigating the change of wear life and the influence of temperature on the reliability of the film by investigating the hydrogen-containing fullerene films.On the other hand,the defects of the solid lubricating film are improved by using solid-liquid composite lubrication.1.The hydrogenated fullerene-like carbon(FL-C:H)films was grown on the surface of the silicon wafer by DC plasma enhanced chemical vapor deposition.The structure of the film was confirmed by scanning electron microscopy(SEM),high resolution transmission electron microscopy(HRTEM)and Raman spectroscopy.The hardness of the film at the wear stage was measured by nano indenter.The friction coefficient and the life span of the film under different loads were studied by using the ball disc reciprocating friction and wear tester made by Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences.The relationship between the change of film life under different loads and the film hardness was discussed.By measuring the surface hardness of hydrogenated fullerene-like carbon films with different time of friction under load of 10N,20N and 25N,it can be concluded that under the action of load,plastic deformation occurs in the surface of the film during the running-in period and the hardness of the films increases.When the friction coefficient is stable,the surface hardness remains stable within a certain range.When the load becomes larger,the initial surface hardness of the film also increases accordingly.According to the Archcard law,we can achieve the rule of TW=(Db/k)H.The product of the wear time(wear life)T of hydrogenated fullerene-like carbon films and the load W and the product of the total thickness D and the wear width b and the wear coefficient k ratio is proportional to the hardness of films.The conclusion can be proved that it is reliable from the point of experiments.It can be explained that with the load increases,the film friction coefficient decreased and its wear life remained stable phenomenon,that is,the load increases,the film surface hardness also increases,so the wear and tear weakened,making the wear life and stability.2.The thermal stability of hydrogenated fullerene-like carbon films was investigated by annealing the films in nitrogen.The structure changes and friction and wear properties of films before and after annealing were characterized by elastic recoil detection(ERD),high resolution transmission electron microscopy(HRTEM),Raman spectroscopy and X-ray photoelectron spectroscopy(XPS)and nano indenter at annealing temperatures of 200,250,300,500℃.When the annealing temperature is lower than 300℃,the fullerene-like feature of the film increases with the increase of annealing temperature,the hardness of the film increases and the wear volume decreases.The sp~2 atoms in the thin film annealed at low temperature(250~300℃)are transformed into sp~3 atoms.With the increase of annealing temperature(400 and 500℃),the sp~3 atoms of the film are transformed into the sp~2 atoma,and the film begins to graphitize.Hydrogenated fullerene-like carbon films have the best friction and wear properties at annealing temperature of 300℃.3.A lubricational system is investigated in this article that the frictional interface of two hydrogenated fullerene-like carbon(FL-C:H)films with the base oil(Poly Alpha Olefins Type6:PAO6)added by reduced graphene oxide(RGO)(FL-C:H/(PAO6+RGO)/FL-C:H).FL-C:H films were deposited on steel balls(GCr15)and silicon crystal plates(100)using plasma enhanced chemical vapor deposition systems.The tribological performances between the uncoated or coated balls and the FL-C:H films were investigated under the lubrication of the base oil with the addition of RGO.The results indicate that FL-C:H films and RGO have synergistic effects on the reduction of friction and wear.The FL-C:H/(PAO6+RGO)/FL-C:H system not only improves the lubrication and anti-wear ability,but also possesses remarkable potential meaning of tribological application. |
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