Effects Of Probe Wear And Laser Irradiation On The Tribological Properties Of Molybdenum Disulfide

Two dimensional MoS₂ is a layered material with weak Van der waals forces between layers.It has excellent tribological performance because of the special property of MoS₂ .The effects of probe wear and laser irradiation on its tribological properties were investigated based on the perspective of nano-tribology.As for tip wear,we combined with the advanced scanning electron microscopy?SEM?and atomic force microscope?AFM?to investigate the effects of tip radius of probe on the accuracy of surface friction,adhesion and critical shear stress for MoS₂ sample during the friction experiment.The tribological properties of MoS₂ nanosheet were measured by using AFM under laser irradiation with the different wavelength and intensity.It is of great significance to research the effects of tip wear and light irradiation on the tribological properties of MoS₂ nanosheet.The specific research contents and results are as follows.?1?MoS₂ nanosheets were prepared by improving the process parameters of chemical vapor deposition?CVD?,and a relatively intact two-dimensional MoS₂ nanosheets with thin layer were successfully obtained.?2?The experimental device was built to investigate the friction performance of MoS₂ samples under laser irradiation before the laser light source was imported into AFM chamber via optical fiber?3?The tip radius of the probe at isometric sampling points with different sliding distances were measured by SEM.The atom-by-atom wear model was used to obtain tip radius value of the whole sliding process.It is proved that the atom-by-atom wear model is more suitable to describe the process of tip radius changing with sliding distance than Archard model.The critical shear stress during probe wear was measured by B-JKR model.?4?Under laser irradiation,we found that the surface friction of odd-layer nanosheet was reduced,however the surface friction of even-layer nanosheet was increased.?5?With the increase of laser irradiation intensity,the decrease of MoS₂ friction in odd layers gradually increases,and the increase of MoS₂ friction in even layers gradually increases.