Inorganic nanomaterial lubricant additives for base fluids, to improve tribological performance: Recent developments

Abstract

In this paper, we review recent research developments regarding the tribological performances of a series of inorganic nano-additives in lubricating fluids. First, we examine several basic types of inorganic nanomaterials, including metallic nanoparticles, metal oxides, carbon nanomaterials, and “other” nanomaterials. More specifically, the metallic nanoparticles we examine include silver, copper, nickel, molybdenum, and tungsten nanoparticles; the metal oxides include CuO, ZnO, Fe3O4, TiO2, ZrO2, Al2O3, and several double-metal oxides; the carbon nanomaterials include fullerene, carbon quantum dots, carbon nanotubes, graphene, graphene oxides, graphite, and diamond; and the “other” nanomaterials include metal sulfides, rare-earth compounds, layered double hydroxides, clay minerals, hexagonal boron nitride, black phosphorus, and nanocomposites. Second, we summarize the lubrication mechanisms of these nano-additives and identify the factors affecting their tribological performance. Finally, we briefly discuss the challenges faced by inorganic nanoparticles in lubrication applications and discuss future research directions. This review offers new perspectives to improve our understanding of inorganic nano-additives in tribology, as well as several new approaches to expand their practical applications.

Synthesis of Eco-Friendly Carbon Dots as Self-Repairing Additives of Polyalphaolefin by Means of a Green Solvation Effect

“…Actually, the dispersion stability of CDs-Menth/PAO4 lubricant in this work is far superior to most of reported nano-based lubricants no matter containing dispersants or not. 58 The effects of concentration (c) on tribological properties of CDs-Menth/PAO4 lubricants were investigated under load of 40 N and duration of 20 min. Figure 5a shows that the friction coefficient curve of PAO4 is fluctuated at a high level between 0.15 and 0.20, reflecting the inadequate lubricity of PAO4 itself under boundary lubrication regime.…”

Typical dampers and energy harvesters based on characteristics of ferrofluids

“…In 1965, Stephen [1] from National Aeronautics and Space Administration (NASA) successfully prepared stable ferrofluids for the first time, after which many of the properties of ferrofluids were investigated, including their levitation characteristics [2,3], rheological properties [4,5], magnetization characteristics [6], magnetoviscous effect [7,8], magnetocaloric effect [9,10], and magneto-optic effect [11,12]. Ferrofluids have a wide range of industrial applications such as seals [13][14][15], dampers, sensors [16,17], lubrication [18][19][20], biomedicine [21], and finishing [22,23]. Although the statistics are incomplete, there are more than 170 applications for ferrofluids, many of which cannot utilize other materials.…”

Low-Temperature-Graphitized and Interpenetrating Network C/Fe3O4 Magnetic Nanocomposites with Enhanced Tribological Properties under High Temperature

“…Friction can be seen everywhere in our daily life, reducing friction and wear can effectively extend the service life of a machine, reduce energy consumption, and have a huge role in promoting industrial development. Recently, nanomaterials including metal nanoparticles (NPs), inorganic NPs, and polymer NPs have been used as lubricant additives, which show outstanding anti-friction and anti-wear properties. − Among them, magnetic NPs, such as MnZnFe 2 O 4 , CoFe 2 O 4 , and Fe 3 O 4 , have received widespread attention because of their potential to reduce the cost of treatment and recycle waste oil. − These magnetic nanomaterials are easily adhered on the surface of the friction pair due to their magnetism. Therefore, a friction self-healing film is formed on the sliding surface, which has an anti-friction effect.…”