Synthesis and tribological properties of Mo-doped WSe2 Nanolamellars

The Mo-doped WSe2 nanolamellars have been successfully prepared via solid-state thermal (750 °C) reaction between micro-sized W, Mo with Se powders under inert atmosphere in a closed reactor and characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the morphologies of the as-prepared products changed from microplates to nanolamellars to aggregations composed of nanoparticles with the doping of Mo powders. And the sizes of crystallites evidently reduced while the contents of dopant increased within a certain limit (1 wt.%–7 wt.%). The tribological properties of the as-prepared products as additives in HVI750 base oil were investigated by UMT-2 multispecimen tribotester. The friction coefficient of the base oil containing Mo-doped WSe2 nanolamellars was lower and more stable than that of WSe2 nanolamellars. A combination of rolling friction, sliding friction, and stable tribofilm on the rubbing surface could further explain the good friction and wear properties of Mo-WSe2 nanoparticles as additives than that of WSe2.