Synergistic effect of binary systems of nanostructured MoS₂/SiO₂ and GO/SiO₂ as additives to coconut oil‐derived grease: Enhancement of physicochemical and lubrication properties

Abstract

The present work addresses the use of synergistic blends of two different types of nanomaterials (spherical particles and lamellar sheets) as additives for coconut oil‐based grease formulation to provide the energy‐efficient and sustainable alternative to conventional grease. The spherical SiO2 nanoparticles are separately blended with 2D lamellar sheets of MoS2 and graphene oxide (GO) in variable ratio and probed their synergistic effects for enhancement of physicochemical and lubrication properties. The SiO2 nanoparticles, MoS2, and GO nanosheets are prepared by modified sol–gel, hydrothermal reduction, and Hummer's methods, respectively. The 0.05 wt% nanomaterials blends of MoS2/SiO2 (30:70) and GO/SiO2 (50:50) as optimised doses furnished the maximum reduction in the friction and wear. The combination of rolling friction and low shear properties using the synergistic blend of the spherical nanoparticles (SiO2) and nanosheets (MoS2 and GO) showed significant improvement in tribological properties. The optimised blends of nanoadditives, that is, MoS2/SiO2 and GO/SiO2 conserved the energy by 20% and 19%, respectively. These findings suggest that the use of synergistic blends of variable nanomaterials to vegetable oil‐based lubricants can pave a direction for new generation lubricant formulation, where environmental sustainability and energy conservation are on prime importance.

Tribological evaluation of PAO 100 oil‐based lithium greases with chemically functionalized nanoadditives

“…The kurtosis value greater than 3 () of centrally distributed topography height distribution is regarded as a leptokurtic surface, demonstrating a spiky surface (i.e., relatively many high peaks and low valleys). In contrast, well‐spread height distribution acquires a kurtosis value lower than 3 () is known as platykurtic surface, which features relatively few high peaks and low valleys 60,61 . Therefore, all worn surfaces owing (as shown in Table 6) are platykurtic surfaces.…”

“…In contrast, well-spread height distribution acquires a kurtosis value lower than 3 (S ku < 3) is known as platykurtic surface, which features relatively few high peaks and low valleys. 60,61 Therefore, all worn surfaces owing S ku < 3 (as shown in Table 6) are platykurtic surfaces.…”

Effect of polymer additives on the tribological performance of soybean oil

“…The lubrication process of the composite nanofluid was studied, as well as the process by which the composite lubricating film develops (Meng et al , 2021). Rawat et al (2021) developed vegetable oil-based grease using coconut oil and metallic lithium soap as gelling agents. Wet chemically processed SiO 2 , MoS 2 and GO nanosheets are nano-additives to coconut grease.…”

“…Wet chemically processed SiO 2 , MoS 2 and GO nanosheets are nano-additives to coconut grease. The effect of these two nanoadditives on grease’s physicochemical and tribological properties is analysed (Rawat et al , 2021). Mobarhan et al (2022) used synthesized spherical MoS 2 to investigate the effects of their concentration with compressor oil on wear properties.…”

Study on anti-wear and friction-reducing compounding additives in lithium greases

“…In practical applications, friction modifiers and anti-wear additives are often used in combination to promote functional complementarity between single additives and produce synergistic effects (Rawat et al , 2021; Dawczyk et al , 2019). The simultaneous addition of ZDDP and organic anti-wear additives improved the formation and surface coverage of the friction film, as well as the anti-wear properties of the friction surface (Burkinshaw et al , 2014).…”