Theoretical And Experimental Coupling Study On Friction Interface And Tribological Behavior Of Carbon Based Films With Copper

Diamond-like carbon(DLC)films have attracted more and more attention on account of their low friction coefficient,high hardness,good chemical stability and corrosion resistance.Tribological behavior of Cu is peculiar among soft metal when it rubs on diamond flat or DLC films in experiments,and passivating element F and H at Cu/Diamond interface can affect mechanical properties and even tribological characteristics as well,related special adhesive transfer and adhesion tuning mechanism at Cu/Diamond interface remain obscure.Here,in the first part of this paper,the interfacial structure change,electronic and mechanical properties of Cu/Diamond and interface with passivation is analyzed through first-principles calculations.The study shows that Cu/Diamond interface exhibits the special phenomenon of adhesive transfer due to adhesion,and this contribute to different frictional properties among soft metal.The effect on the mechanical properties of F and H at Cu/Diamond interface is studied systematically,passivation of fluorine on diamond surface reduces work of separation of the interface significantly.Combining with kinetic analysis,we predict that fluorine has great potential for the improvement of the tribological properties of Cu/Diamond system.In the second part,the tribological properties of copper against DLC films with different hydrogen content were studied through friction experiment and simulation,the effects of hydrogen atoms on friction interface tuning were also discussed simultaneously.The results showed that friction interface is of great importance to tribological performance of Cu/DLC films,and hydrogen atoms can play a role in tuning the friction interface by reducing adhesion at interface.The interaction at interface can be changed by doping modified elements into DLC film so as to improve the tribological performance of Cu/DLC system.Conclusions above can provide references for understanding the tribological behavior of Cu/Diamond system from atomic to macro scale,and promote the application of diamond-like carbon films in engineering field.