Tribological performance of a novel metal-organic framework as a nanolubricant additive

Metal-organic frameworks (MOFs), as lubricant additives, have remarkable potential in super lubrication performance because of their big surface area, tunable chemistry, load bearing capacity, corrosion protection and environmental friendliness. However, only a small number of MOFs are capable of melting. In this paper, Zeolitic Imidazolate Framework-8 (ZIF-8) nanoparticles (diameter of 100 nm) were practically produced and incorporated with a hydrophobic ionic liquid (IL) to develop a novel high-performance MOFs-based ZIF-8@IL nanolubricant additive. Then reciprocating tribological experiments were conducted across a range of ZIF-8@IL concentrations addition in the 150 SN base oil. With respect to using the plain oil, the using of addition of ZIF-8@IL exhibits very good lubrication performance and the optimized case was achieved with the incorporation of a 4.0 wt.% ZIF-8@IL additive, resulting in a decrease of about 27% in coefficient of friction (COF) and 20% in the wear track width. The notable lubrication achievement is due to the collective effects of rolling, mending, polishing, and tribofilm formation. In addition, the use of ZIF-8@IL nanolubricant demonstrated an obvious inhibition of oxidational wear. The findings in this study offer valuable insights to promote the development of high-efficient MOFs-core nanolubricant additive.