The Preparation Of Anti-High Humidity MoS₂-Based Solid Lubricating Coating And The Investigation Of Its Tribological Behavior

Molybdenum disulfide,an excellent solid lubricating material,is widely used in the aerospace field for its excellent tribological properties in the space environment with high vacuum,strong radiation and low temperature.Although MoS₂ has excellent friction performance in the vacuum environment,its performance is very poor in the high-humidity environment,which greatly limits its application.To this end,the two series of MoS₂-based coatings,C-Ti/MoS₂ and MoS₂/Zr,were prepared by doping and structural design,and their tribological mechanism was studied.The SEM,HRTEM,XPS,AFM and XRD were used to characterize the structure of the coating and the nano-indenter was used to evaluate the mechanical properties.The CSM vacuum friction tester was used to test the friction properties of the coating at high humidity and vacuum.The profilometer,Raman spectrometer,optical microscope,SEM&EDS and FTIR Spectrometer were used to characterize the wear track and transfer film,and the corrosion performance of the coating was also tested by electrochemical experiments.The results show:（1）The research on C-Ti/MoS₂ series coatings.A superlattice structure with a modulation period of 7.5 nm was observed.The co-doped coatings with C and Ti have better mechanical and tribological properties than those of the single-doped ones,and the better mechanical properties are related to the formation of C-Mo,Ti-S and Ti-O bonds.The degree of friction-induced graphitization on the wear tack and the quality of the transfer film formed on the wear scar are the key factors affecting the tribological performance of the coating.The reasonable doping can promote the formation of the high-quality transfer film by interacting with water molecules.（2）The research on MoS₂/Zr series coatings.By adjusting the content of the doping Zr,the continuous evolution of structure from the composite to the nano-multilayer is realized,and the minimum modulation period is only 3.61 nm.In the high-humidity environment,the transfer film directly determines the friction performance of the coating,and the H/E（hardness to the elastic modulus）ratio that is a usual index for evaluating wear needs to be revised to be more reliable by adding the influence of water vapor.Friction induced an increase of the crystallinity of the coating.The air-formed oxide layer on the MoS₂/Zr coating has a double-layer structure.The passivation of Zr and the dense and uniform nano-multilayer structure are the main reasons of the excellent corrosion performance.