Abstract
The layered double hydroxide (LDH) is a kind of natural mineral, which can also be manually prepared. It has been practically applied in various fields due to its unique crystal structure and diversity of composition, size, and morphology. In this work, LDHs with different chemical compositions (Co2+, Mg2+, Zn2+, and Ni2+) and topographical features (flower-like, spherical, and plate-like) were successfully prepared by controlling the reaction conditions. Then, they were mechanically dispersed into base grease and their tribological properties were evaluated by a ball-on-disk tester under a contact pressure of 2.47 GPa. It was found that the variation of morphology, instead of chemical composition, had great influence on the tribological performance. The “flower-like” LDH sample with high specific surface area (139 m2/g) was demonstrated to show the best performance. With 1 wt% additive, the wear volume was only about 0.2% of that lubricated by base grease. The tribofilm with unique microscopic structure and uniform composition was derived from tribochemical reaction between LDH additives and sliding solid surfaces, effectively improving tribological properties of the lubrication system. This work provided the guidance for optimizing lubricant additives and held great potential in future applications.
Highlights
IntroductionUnnecessary friction and related wear may cause huge losses, accounting for about 5% to 7% of their gross national product in highly industrialized countries [1,2,3]
Friction is quite common in our daily life and industrial activities
The morphology and crystal structure of these layered double hydroxide (LDH) samples can be determined by their SEM images and X-ray diffraction (XRD) patterns shown in Figs. 2(a) and 2(b)
Summary
Unnecessary friction and related wear may cause huge losses, accounting for about 5% to 7% of their gross national product in highly industrialized countries [1,2,3]. As compared with ordinary nanoparticles as lubricant additives, two-dimensional materials possess smaller longitudinal dimension so that they are much easier to enter the contact area between sliding solid surfaces [7]. A large variety of layered materials such as MoS2 [7,8,9,10], black phosphorus [11, 12], and graphitederived materials [13,14,15,16,17], have been most widely reported because of relatively high specific surface area for good dispersion in lubricant and relatively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
