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 use 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 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.