Preparation Of Molybdenum Disulfide/Carbon Film And Vacuum Tribproperties

The development of space equipment is moving towards heavy-duty,large-scale,and long-term operation,which requires high-performance space lubrication materials.However,current space solid lubrication films,such as molybdenum disulfide and soft metals,can only function at low loads（<0.5 GPa）.Therefore,there is a need to develop solid lubrication film materials/systems for medium to high loads.This article focuses on the surface and interface components of moving space components and utilizes the low shear and high hardness,low friction and wear characteristics of molybdenum disulfide layered carbon film（DLC）to design surface molybdenum disulfide/carbon composite structures,molybdenum disulfide/carbon multi-layer structure films,and interface heterojunction pair systems.The tribological properties of these thin films/systems under vacuum were systematically investigated,revealing the mechanism of the influence of surface interface structure on their vacuum tribological properties.The following main research results have been obtained:1.The present study reports the successful preparation of MoS₂/DLC composite films using unbalanced Magnetron sputtering.The cross-sectional analysis of the composite films revealed a tight structure with no obvious columnar structure of MoS₂.The surface morphology of the films also showed a significant change,with the disappearance of MoS₂worm-like characteristics and the appearance of an island structure formed by aggregated particles.The addition of amorphous carbon improved the poor crystallization of MoS₂and promoted the preferred orientation growth of MoS₂.The hardness of the composite films was found to be significantly higher than that of pure MoS₂films,with an increase from 1.05 GPa to 8.12 GPa.Additionally,the roughness of pure MoS₂films decreased from 5.893 nm to 1.662 nm.The friction and wear test results showed that the composite film exhibited a longer friction life compared to pure DLC film.Furthermore,under vacuum wide load conditions,the wear rate of the composite film was reduced by three orders of magnitude compared to pure MoS₂thin films.The ultra-low wear of the composite film can be attributed to the presence of layered MoS₂and low shear layered graphene structures.2.The present study focuses on the preparation of MoS₂/DLC nano scale multilayer films using unbalanced Magnetron sputtering.The results indicate that MoS₂/DLC multilayer films exhibit significantly improved properties compared to pure MoS₂films.Specifically,the multilayer films exhibit three times higher hardness, lower friction coefficient（0.04）,and lower wear rate by two orders of magnitude compared to pure MoS₂films.The incorporation of MoS₂layer in the DLC film addresses the vacuum friction failure problem of DLC,while the DLC layer enhances the hardness of the multilayer thin films and reduces the wear rate.HRTEM analysis reveals that the nanoscale layer thickness（0.17 nm）allows more MoS₂and DLC layers to participate in the friction process.Furthermore,the high contact stress and MoS₂can induce disordered amorphous carbon to form ordered graphene bands,which in turn reduces the friction coefficient and wear rate.3.Fullerene-like carbon thin films（FL-C:H）were prepared using the PECVD method,and their vacuum tribological properties were investigated with different matching pairs.The results indicate that the heterojunction pair consisting of FL-C:H and MoS₂exhibits low friction coefficient（0.02）and low wear rate(10^-11mm³/Nm)in vacuum(5×10^-3Pa).The abrasive debris of this heterogeneous pairing system contains a significant amount of MoS₂and ordered graphene sheets,suggesting that the FL structure undergoes reconstruction into short-range ordered graphene sheets under the catalysis of low shear force and Moatoms.This process achieves low friction and wear performance in vacuum.