The Self‐Ordered Lamellar Texture of MoS₂ Transfer Film Formed in Complex Lubrication

Abstract

In virtue of the porous microstructure and permeability of a novel MoS2 coating constituted of loosely stacked nanosheets, low viscous polyalphaolefin‐4 lubricating oil is infused to form a solid–liquid complex lubrication coating. Compared with single lubrication mode, complex lubrication shows noticeable reduction of friction as the friction coefficient is just one‐fourth of that for solid coating and half of that for lubricating oil; meanwhile, the load‐carrying capability is drastically improved by more than six times and the lifetime is greatly prolonged from 1300 to beyond 16 000 cycles even under the high contact pressure of 0.5 GPa. Detailed microscopic observation and analysis are conducted to explore the reason behind this excellent performance. A thin, coherent MoS2 transfer film is found to cover the whole contact area on counter surface. The high‐resolution cross‐sectional view further shows there is highly ordered lamellar texture inside the transfer film. Through effective physical adhesion and reorientation, this self‐ordered texture plays a key role in lubrication process. It endows the MoS2 with high‐performance lubrication irrespective of the initial orientation. Meanwhile, this finding gives evidence that the lubricity of MoS2 strongly depends on the cleavage within the crystallites rather than intercrystallite slip.

Superlubricity of Titanium Alloy Enabled by MoS2 Flakes and a-C:H Film

“…In contrast, the II region is filled with curved graphene with an interlayer distance of 0.33 nm. In fact, during the sliding process, superlubricity can be triggered by many factors such as the applied load, the environment, shear stress, and the frictional chemistry of the contact area [40,41]. It has also been shown that the composite films of MoS 2 produced an ultra-low friction phenomenon, which was attributed to the fact that the sliding direction was related to the friction-induced direction parallel to the shear plane of the lamellar structure [42].…”

Template-free scalable growth of vertically-aligned MoS2 nanowire array meta-structural films towards robust superlubricity

“…As a result, the in situ formation of Ag@MoS 2 nanoscrolls (NSCs) with MoS 2 sheets as rolls that wrap the nc-Ag NP cores is physically preferential. 59 Moreover, the rolling of nano-scrolls and onion-like nanostructures is more efficient in reducing motion resistance than sliding. [60][61][62] Once formed, the NSCs slide against randomly-arranged 2D MoS 2 sheets and nc-Ag NPs, which provide continuous incommensurate contact sites.…”