Magnesium Silicate Hydroxide–MoS₂–Sb₂O₃ Coating Nanomaterials for High-Temperature Superlubricity

Abstract

Expanding the low-friction temperature range of molybdenum disulfide-based coatings has been a topic of intense research interest. This paper introduces a coating concept, enabling achieving macroscale superlubricity, or near-zero friction, when exposed to open-air and high-temperature sliding conditions. This low-friction composite coating with a thickness of approximately 150−250 nm was accomplished by uniformly burnishing hydrothermally synthesized lamellate magnesium silicate hydroxide with an average diameter of 50 nm and an average thickness of 10 nm, molybdenum disulfide, and antimony trioxide powders onto a copper substrate. The tribological experiments performed in an open-air environment revealed that with the increase of testing temperature up to 200 °C or above (up to 300 or 400 °C), the coefficient of friction of the composite coating rapidly decreases and finally reaches the superlubricity state (the coefficient of friction is lower than 0.01). This intriguing superlubricity performance is attributed to the synergistic characteristics of lubricating antimony trioxide, molybdenum disulfide, and magnesium silicate hydroxide phases, enabling easy shearing of the film at high-temperature conditions. The results offer an approach for designing a solid lubricant solution for tribological applications.

Achieving Ultralow Friction and Wear by Tribocatalysis: Enabled by In-Operando Formation of Nanocarbon Films

“…Graphene alone was beneficial in lowering the friction and wear of a wide range of metal substrates, but when combined with another form of carbon, such as nanodiamonds, it further enabled the mechanically most desirable state of near-zero friction or superlubricity with no wear damage on sliding contact surfaces (Figure ). In addition to this and other studies demonstrating ultralow friction and wear of 2D materials, , researchers have also achieved very favorable tribological performance using various other carbon forms including nanotube, nano-onions, and nanodiamonds as additives in lubricating oils and other liquids. ,,, In fact, such studies have gained high momentum in recent months with the hope that they can soon be reduced to some industrial products. − …”

Nanomaterials in the Automobile Sector

“…The friction and wear of the worn surfaces is a principal cause of energy dissipation in automobile engines. Nanomaterials are highly promising for utilizing as lubricants, which are called nanolubricants, in automobile sectors since nanolubricants are capable of creating superlubricity [40][41][42][43]. In the automobile lubrication system, the boundary lubrication region is a highly concerned area to be taken care of due to the high friction coefficient.…”

Progress in Superlubricity Across Different Media and Material Systems—A Review

“…Meanwhile, there is a dire need for lubrication solutions in applications involving high-temperature regimes, including all kinds of turbines, transportation and manufacturing operations, and aerospace technology. State of the art of high-temperature lubrication rendering sub-0.01 friction is still in its infancy with a very limited number of studies demonstrating such a phenomenon under some very specific test conditions (Zeng et al, 2015;Gao et al, 2021;Wang et al, 2021).…”

“…Observations of the high-temperature superlubricity were further expanded for the system combining Sb 2 O 3 (base layer) and composite burnished coatings of MSH −MoS 2 (Wang et al, 2021). The high-temperature superlubricity was observed only at temperatures over 100 °C, strongly indicating that evaporation or disassociation of water molecules must have a direct effect on lowering friction.…”

“…The high-temperature superlubricity was observed only at temperatures over 100 °C, strongly indicating that evaporation or disassociation of water molecules must have a direct effect on lowering friction. Wang et al (Wang et al, 2021) revealed that MSH−Sb 2 O 3 −MoS 2 composite coatings rendered respectable lubricity (friction = 0.075) in room temperature experiments, and the performance surprisingly improved by an order of magnitude to the friction coefficient of 0.007 at 200 °C and above. This temperature dependence of friction above the evaporation point of water was deciphered via DSC−TG analysis, which suggested that the temperature increase accelerated the destruction of structural water (hydroxyl group in Mg−O/OH octahedral sheets), its subsequent bonding to the surface elements, and thus directly reducing friction.…”