MoS₂ Lubricating Film Meets Supramolecular Gel: A Novel Composite Lubricating System for Space Applications

Abstract

In the field of space mechanical lubrication, to improve the reliability and life of space lubrication, solid lubricating film–liquid lubricant composite lubrication has been used in recent years. This lubrication method can improve the durability of sliding friction mating surfaces, reduce equipment wear, and extend the service life of motion mechanisms. However, due to unstable factors such as volatilization and creeping of liquid lubricants in microgravity and ultra-high-vacuum environments, the solid lubricating film wears out after long-term use and produces wear debris and other unfavorable factors. To solve the above problems, this study proposes a novel composite lubrication system constituting a MoS2 film in combination with a supramolecular gel. The tribological performance of this lubrication system establishes an extended service life with a lower wear rate compared to the MoS2 film, regardless of functioning in vacuum or atmospheric conditions. More importantly, the results of the irradiation experiment demonstrate that MoS2–gel exhibits better anticreep performance as compared to MoS2–oil when exposed to atomic oxygen and ultraviolet light for 4 h. The analysis of this composite lubrication mechanism also reveals the formation of a continuous transfer film on the surface of the friction pairs by virtue of the outstanding synergistic effect between the MoS2 film and the gel. MoS2 debris is present in the gel as an additive, and the gel is capable of replenishing automatically once the MoS2 film is depleted. Moreover, the strong anticreep properties of the gel are attributable to the multialkylated cyclopentane oil being trapped by the intricate reassembling of the gelator network. It is firmly believed that this novel MoS2–gel composite lubrication system may have good prospective applications in space and special machinery domains.

Tribological gain enabled by the synergy of copper nanoparticles and friction induced in situ tribo-click reaction

“…but act in a similar way-by creating a stable lubricating lm between the friction interfaces to obtain a signicant friction-reduction and antiwear effect. 3,9,10 The establishment of such lubricating lms oen relies on the complex physicochemical changes that occur between the lubricant and interface during the friction process. 11,12 The study of tribochemistry focuses precisely on the rapid energy transformations and physicochemical changes at the friction interface when lubricated materials are in use.…”

Recent advances of two-dimensional lubricating materials: from tunable tribological properties to applications

“…139 Accordingly, the construction of solid/ liquid composite lubrication systems, such as WS 2 -MoS 2 /MAC composite, MoS 2 -Au/Au multilayer and MoS 2 -gel composite, has been proven to be an advanced strategy to solve the abovementioned problems. 137,[140][141][142][143] For example, an MoS 2 -gel composite exhibited a longer service life, lower wear rates, and better lubricity than pure MoS 2 lm. 137 The MoS 2 -gel composite could not only isolate the moisture of the air from the MoS 2 lm but also form a transfer lm on the upper ball to generate a boundary lubrication lm on the surface of the friction pair, promoting the desirably enhanced lubrication performance of the MoS 2 multilayer lm system (Fig.…”

“…137,[140][141][142][143] For example, an MoS 2 -gel composite exhibited a longer service life, lower wear rates, and better lubricity than pure MoS 2 lm. 137 The MoS 2 -gel composite could not only isolate the moisture of the air from the MoS 2 lm but also form a transfer lm on the upper ball to generate a boundary lubrication lm on the surface of the friction pair, promoting the desirably enhanced lubrication performance of the MoS 2 multilayer lm system (Fig. 9a).…”

Thiadiazole Dimer-Functionalized Liquid Metal Nanoparticles for Anti-Corrosion and Friction Reduction

“…Lubricants play an imperative role in ensuring the efficient and safe operation of mechanical systems. , However, some machines are required to operate under specific conditions, such as in aerospace or marine environments. , Traditionally, lubricants have been incapable of protecting mechanical systems from the harsh working conditions that can cause lubrication failure between friction pairs. These conditions include extreme loads, high temperatures, frequency conversion, and corrosive media.…”