Cailiao Baohu (Apr 2024)
The Effect of Graphene Layer Number on Dispersibility and Tribological Performance
Abstract
In order to improve the tribological performance of transmission oil base oil and explore the influence of graphene layers on it, the graphene nanosheets with different layers and nano graphite(NG) were selected as lubrication additives for transmission oil base oil, and the lubrication characteristics of different layers of graphene and nano graphite transmission oil base oils were tested by UMT-3 reciprocating friction tester. Results showed that the dispersion stability of graphene with different layers in transmission oil base oil was different. Among them, single-layer graphene had the best dispersion stability due to its large surface area and weak interlayer forces, and oil molecules could fully fill the graphene interlayer and cause steric hindrance effects, which endowed it with the best dispersion stability. Moreover, all graphene with different layers and NG as lubricating additives for transmission oil could improve the lubrication characteristics of the transmission oil base oil. Therein, single-layer graphene(SGN) transmission oil exhibited the best tribological performance, with a 98% reduction in wear amount compared to base oil. In addition, the significant graphene peaks were detected in Raman tests on the worn surfaces lubricated with graphene and NG transmission oil, indicating that the adsorption of graphene and NG in the friction area formed a dense friction film, thereby reducing the friction coefficient and wear rate. Collecting and observing the friction products of SGN transmission oil effectively revealed its lubrication mechanism. Besides, the excellent tribological performance of SGN was mainly attributed to its excellent dispersion stability and the structural ordering transformation that occurred under shear action.
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