Preparation of Nanofluid of Lanthanum Borate Nanosheets and Investigation of Its Tribological Properties and Tribomechamisms in Different Base Oils

Abstract

Oleic acid-modified lanthanum borate nanosheets (OA-LBNs) were prepared by simple surface modification technology combined with precipitation method. The structure of the as-prepared light yellow transparent nanofluid of OA-LBNs was analyzed by Fourier transform infrared spectroscopy and transmission electron microscopy, and its thermal stability was evaluated by thermogravimetric analysis. Moreover, the tribological properties of OA-LBNs nanofluid as the lubricant additive in diisooctylsebacate (DIOS), poly-α-olefin (PAO4), and rapeseed oil (RO) were evaluated with a four-ball friction and wear tester, and its tribomechanisms in the three kinds of base oils were also discussed. The results show that OA-LBNs nanofluid exhibits good antiwear ability in the three kinds of base oils; and in particular, OA-LBNs nanofluid added in PAO4 shows the best antiwear ability. The tribological properties of the OA-LBNs nanofluid as the lubricant additive are dependent on the nature of the base oils. Namely, the polarity of the base oil influences the adsorption of the OA-LBNs nanofluid on the rubbed steel surface, thereby affecting the composition of the tribofilm formed on the rubbed steel surface and resulting in changes in tribological properties.

Carbon Dot-Based Nanofluids as Additives for Mechanical Lubrication

“…3 Although the commercial lubricant additives of organomolybdenum compounds and zinc dialkyldithiophosphates (ZDDP) containing high phosphorus and sulfur contents have shown the particularly highperformance price ratio, they are attracting more and more environmental concerns because of their hazardous effects and difficulty of disposal/degradation. In the past several decades, various nanoadditives, including metal, 4 metallic oxide, 5 metal salt, 6 graphene, 7 mesoporous carbon, 8 carbon nitride, 9 boron nitride, 10 MXene, 11 and composite, 12 have been applied as the lubricant additives and exhibited the outstanding frictionreducing, antiwear, and extreme pressure properties. The nanoadditives were considered to be ideal candidates for conventional additives.…”