MoS2 nanoparticles have been considered valuable materials in lubricating applications due to their layered morphology. This work synthesized spherical MoS2 nanoparticles that held many nanosheets through the hydrothermal method. The thickness of these sheets is between 10 and 25 nm, and their length is estimated to be about 200 nm. The effect of nanoparticles concentration on wear properties was investigated in this research. The four-ball test measured the wear performance of nano lubricants. The results showed that all nano lubricants had better wear performance than the base lubricant (Behran Compressor 68). However, molybdenum disulfide nanoparticles synthesized as nanosheets with a thickness of 10 nm had the best performance. At a concentration of only 0.05 wt-%, the resulting nano lubricant reduced the wear width and friction coefficient by about 50%. The thermal conductivity coefficient results also showed that nanoparticles increased this coefficient. As the lubricant temperature increases, the difference between the nano and base lubricant's thermal conductivity increases. 相似文献
MoS2 coatings, 55–800 nm thick, were grown by ion-beam-assisted deposition (IBAD) using different ion-to-atom ratios and deposition temperatures. Crystallinity and orientation of the IBAD MoS2 coatings were determined by X-ray diffraction (XRD). Only XRD peaks corresponding to (00l), (hk0), and amorphous MoS2, and a previously unreported low-2Θ peak (2Θ ≈ 10.7 °) were observed. The basal (002) peak intensities varied primarily with ion-to-atom ratio; the greatest basal intensity occurred when the ion-to-atom ratio produced about 1 displacement per atom. Although a secondary factor in basal intensity, deposition temperature was the primary factor in edge (100) intensity. Edge intensity increased with increasing temperature; it appears that the increases are due to annealing of randomly-oriented MoS2, which converts to edge orientation. The origin of the low-2Θ peak is unknown, but appears to be associated with the basal planes of MoS2. 相似文献
In the recent years, transition-metal dichalcogenides such as MoS2 have attracted considerable attention owing to their unique structure and electronic properties. Chemical vapor deposition (CVD) is a popular method for producing MoS2 flakes with different shapes. Here, we report an effective method for achieving a broad range of shape evolution in CVD-grown monolayer MoS2 flakes. By controlling the S and MoO3 temperatures, the shape of the monolayer MoS2 flakes was varied from hexagonal to triangular via intermediate shapes such as truncated and multi-apex triangles. The shape evolution of the MoS2 flakes can be explained by introducing the term “nominal Mo:S ratio”, which refers to the amount of loaded MoO3 and evaporated S powders. By using the nominal Mo:S ratio, we predicted the potential reaction atmosphere and effectively controlled the actual proportion of MoO3−x with respect to S in the growth region, along with the growth temperature. From the systematic investigation of the behavior of the shape evolution, we developed a shape-evolution diagram, which can be used as a practical guide for producing CVD-grown MoS2 flakes with desired shapes.
In this work, finite-element analysis method is adopted to simulate Al particle deposition behavior on Mg substrate by cold spray. The effects of particle parameters such as incident velocities and angles, particle sizes, and number and types of incident particles on impacting character are analyzed. The particle energy, effective plastic strain, and its temperature distribution are discussed. Results reveal that increasing the particle incident velocity can intensify the deformation of both particle and substrate. The bonding will also be strengthened. Incident angles will also affect the bonding between particles and substrate. In multiple particle deposition process, the compaction effect of subsequent particles can promote the deformation of former particles and its bonding with substrate. Temperature distribution and the effective plastic strain distribution are consistent: temperature is higher in the area where the plastic deformation and stress is higher. Local melting may occur in that area at high temperature. 相似文献