Abstract:
Molybdenum disulfide (MoS
2) is easy to be oxidized when used at high temperature, which leads to significant deterioration of its tribological properties, showing a high friction coefficient. In order to improve the tribological properties of MoS
2 lubricant under high temperature environment, core-shell MoS
2@SiO
2 nanocomposites was formed by hydrothermal method and improved Stöber method. The morphology, size and composition of the nano materials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The micro results show that the core-shell structure composite is successfully prepared, with an average particle size of 250 nm. The high temperature friction test of prepared MoS
2@SiO
2 solid lubrication coating was carried out, and the MoS
2 coating was used as a comparison. The morphology and structure of the coating were characterized by SEM and XRD, and the wear rate of the coating was characterized by a 3D profiler. The results show that the friction coefficient of the MoS
2@SiO
2 coating at 680℃ is 0.2 and relatively stable, while MoS
2 coating rapidly fail. The MoS
2@SiO
2 coating had better wear resistance, with a wear rate at 25.86%, lower than that of MoS
2 coating. After the friction tests, MoS
2 still existed in the wear scar area of the MoS
2@SiO
2 coating, which was covered by the lubricating film. However, the substrate in the wear zone of MoS
2 coating was completely exposed. It is thus shown that the encapsulation of the SiO
2 shell retards the rapid oxidation of MoS
2 at high temperatures and the two synergistically lubricate to prolong the service life of the coating.