| DLC-based solid-liquid synergetic lubricating system has wide application prospect in the fields of aviation,automobile because of its outstanding antifriction and antiwear properties.The existing additives which are designed on the basis of interaction with the metal surface cannot match the DLC-based films.Based on the activity of Cu nano-particle with both DLC-based film and metal materials,a new way is provided aiming at developing new type additive for the DLC-based solid-liquid synergetic lubricating system.In this study,in order to explore the lubrication mechanism of nano additives in carbon film solid-liquid composite lubrication system,the influence of carbon film mechanical properties,system base oil type and nanometer additive surface modification on the friction properties of nanometer copper additive in the system was systematically studied.The result and conclusion were listed in the following three aspects.1.The influence of carbon film mechanical properties on Cu nanoparticles friction behavior in solid-liquid composite lubrication systemFour kinds of DLC film with different hardness(pure carbon film,doped Si carbon film,mixed with Al carbon film,H carbon film)were used in PAO/DLC solid-liquid composite lubricating system.The tribological mechanism of NPCuDDP in these systems was studied.For comparison,friction properties of traditional additive dialkyl disulfide generation of zinc phosphate(ZDDP)in systems were also evaluated.Examine carbon film mechanical properties of Cu nanoparticles of the solid-liquid composite lubrication system the influence of friction in the region of the boundary lubrication behavior.The results show that with the decrease of DLC film hardness ZDDP cannot form continuous friction reaction film on friction pair,which resulted in the increasing of wear rate of DLC films.Nanometer copper additive with highly active characteristics can form copper friction film with low shear strength on DLC films with different hardness with no choice.Then NPCuDDP shows excellent antifriction and anti-wear properties in all systems(compared with base oil COF decreased by 9%～9%,compared with ZDDP COF reduced by 22%～42%;compared to base oil WR reduced by 93.2%～93.2%,compared to ZDDP WR reduced by 87%～94%).2.The influence of base oil on Cu nanoparticles friction behavior in solid-liquid composite lubrication systemTwo kinds of base oil with different polarity PAO and DIOS were used in DLC solid-liquid composite lubricating systems in order to explore the effect of base oil type on the friction properties of NPCuDDP in DLC solid-liquid composite lubricating system.Results show that the antifriction property of NPCuDDP almost disappeared in DIOS/DLC system because of the competitive adsorption between DIOS and NPCuDDP on friction pairs.However,the anti-wear properties of NPCuDDP in DIOS was the same with that in PAO.(In PAO,compared with ZDDP the COF of NPCuDDP reduced by 13.8%～36%,and in DIOS reduced by 10%～19%;In PAO,compared with ZDDP the wear rate of NPCuDDP reduced by 94%一96%,in DIOS reduced by 92%～96%).For ZDDP the anti-friction and anti-wear behavior in the two kinds of base oil are consistent without chemical environment sensitivity.3.The influence of modifier of Cu nanoparticles on friction behavior in solid-liquid composite lubrication systemTwo kinds of Cu nanoparticle with different modifier(named as NPCuDDP and NPCuDTC)were used in DLC solid-liquid composite systems to research the effect of modifier of Cu nanoparticles.The results show that the antifriction and anti-wear properties of NPCuDTC were not as good as that of NPCuDTC(compared with NPCuDTC the COF of NPCuDDP reduced by 7%～18.3%in the PAO,and reduced by 6%～12.6%in DIOS;wear rate reduced by 40%～70%in PAO,and reduced by 40%～80%in DIOS).The functional groups of Cu nanoparticles modifier played a key role on the adsorption of nanoparticles on friction pair,and then decided the tribological properties of nanoadditives. |
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