Se Nanopowder Conversion into Lubricious 2D Selenide Layers by Tribochemical Reactions

Abstract

Transition metal dichalcogenide (TMD) coatings have attracted enormous scientific and industrial interest due to their outstanding tribological behavior. The paradigmatic example is MoS2, even though selenides and tellurides have demonstrated superior tribological properties. Here, an innovative in operando conversion of Se nanopowders into lubricious 2D selenides, by sprinkling them onto sliding metallic surfaces coated with Mo and W thin films, is described. Advanced material characterization confirms the tribochemical formation of a thin tribofilm containing selenides, reducing the coefficient of friction down to below 0.1 in ambient air, levels typically reached using fully formulated oils. Ab initio molecular dynamics simulations under tribological conditions reveal the atomistic mechanisms that result in the shear‐induced synthesis of selenide monolayers from nanopowders. The use of Se nanopowder provides thermal stability and prevents outgassing in vacuum environments. Additionally, the high reactivity of the Se nanopowder with the transition metal coating in the conditions prevailing in the contact interface yields highly reproducible results, making it particularly suitable for the replenishment of sliding components with solid lubricants, avoiding the long‐lasting problem of TMD‐lubricity degradation caused by environmental molecules. The suggested straightforward approach demonstrates an unconventional and smart way to synthesize TMDs in operando and exploit their friction‐ and wear‐reducing impact.

Unlocking the Potential: Atomically Thin 2D Fluoritene from Exfoliated Fluorite Ore and Its Electrochemical Activity

“…3−5 These extraordinary atomically thin non-van der Waal (n-vdW) materials, such as hematene, 6 ilmenene, 7 biotene, 8 and other newly discovered compounds, present interesting prospects in the field of magnetism, energy harvesting and storage, advanced sensors, optoelectronics, biomedical devices, and ultrafast electronics. Apart from metal oxides, 3 metal selenides, 9 tellurides, 10 and sulfides, the halide group is also interesting for materials and technologies innovation.…”

“…The discovery of graphene initiated the study of 2D materials by revealing the novel properties of exfoliated layered materials. , Studying materials in their ultrathin dimensions revealed numerous cutting-edge properties, thereby expanding opportunities in materials engineering with the recent discoveries of 2D nonlayered materials. − These extraordinary atomically thin non-van der Waal (n-vdW) materials, such as hematene, ilmenene, biotene, and other newly discovered compounds, present interesting prospects in the field of magnetism, energy harvesting and storage, advanced sensors, optoelectronics, biomedical devices, and ultrafast electronics. Apart from metal oxides, metal selenides, tellurides, and sulfides, the halide group is also interesting for materials and technologies innovation.…”