Tribological and rheological properties of the lubricant containing hybrid graphene nanosheets (GNs)/titanium dioxide (TiO ₂ ) nanoparticles as an additive on calcium grease

TiO2 and CeO2 nanoparticles as lithium complex grease additives for enhanced lubricity

“…In recent years, various studies have shown that nanometer-sized oxide particles can significantly improve the anti-wear and anti-friction performance of lubricating greases because of their low melting point and low density (Xia et al , 2022; Ahmed et al , 2020). Nano-TiO 2 and nano-CeO 2 are commonly used metal oxide additives in lubricants and have excellent anti-friction and anti-wear properties (Kamel et al , 2022). Currently, many studies have shown that nano-TiO 2 acts as a filler by aggregating and adsorbing on the surface of the friction pair, generating a lubricating film and enhancing the anti-friction and anti-wear properties of the lubricant (Patel and Kiani, 2019; Zhang et al , 2021).…”

“…Generally, when more than two additives are combined, they can work synergistically in the lubricating grease, leading to better performance compared to using a single additive alone. Kamel et al (2022) used hybrid composite nanomaterials consisting of GNs nanoplates and TiO 2 as additives in lubricating grease. They conducted a study on the tribological properties of these hybrid composite nanomaterials in lubricating grease.…”

Lithium–Calcium Greases Having Carbon Nanotubes and Aluminum Oxide Base Nanoadditives: Preparation and Characteristics of Nanogrease

“…Most additives are unsatisfactory for use due to the pungent odor, corrosion, and friction. , So, recently, nanoadditives were used to enhance the properties of lubricants due to their distinctive rheological − and tribological characteristics, ,, such as tribochemical reactions and friction. Kamel et al ,,,, studied the effect of multiwall carbon nanotubes (MWCNTs) and graphene nanosheets (GNs) when added to calcium grease. The results proved that the tribological and rheological characteristics of modified grease were enhanced at the optimal percent of 3% in both MWCNTs and GNs.…”

“…The main task of grease is to reduce friction and wear between moving parts and increase the machine lifetime. A large amount of energy is dissipated in mechanical systems due to friction and heat at the contact surface. , Therefore, ordinary greases do not provide the required efficiency to overcome the problems of friction, wear, and the dropping point of grease. With respect to long-term growth and development, the most commonly used lubricating greases can be classified into three categories based on their usage principles: calcium grease, lithium grease, and sodium grease .…”

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This research presents the results of the effect of different concentrations (2,4,6, and 8 wt %) of multiwall carbon nanotubes (MWCNTs) and aluminum oxide nanoparticles (Al 2 O 3 ) on the characteristics of lithium−calcium grease (LCG). The LCG/Al 2 O 3 and LCG/MWCNT were studied and illustrated by measuring the dropping point, consistency, thermal conductivity, and tribological characteristics of nanograins (wear, friction, and welding point) by using a four-ball tribometer.

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