Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jul 26;15(15):5177.
doi: 10.3390/ma15155177.

Tribological Behavior of Reduced Graphene Oxide-Al2O3 Nanofluid: Interaction among Testing Force, Rotational Speed and Nanoparticle Concentration

Chenglong Wang  1 , Jianlin Sun  1 , Linghui Kong  2 , Jiaqi He  1
Affiliations

Tribological Behavior of Reduced Graphene Oxide-Al2O3 Nanofluid: Interaction among Testing Force, Rotational Speed and Nanoparticle Concentration

Chenglong Wang et al. Materials (Basel). .

Abstract

The tribological properties of nanofluids are influenced by multiple factors, and the interrelationships among the factors are deserving of further attention. In this paper, response surface methodology (RSM) was used to study the tribological behavior of reduced graphene oxide-Al2O3 (rGO-Al2O3) nanofluid. The interaction effects of testing force, rotational speed and nanoparticle concentration on the friction coefficient (μ), wear rate (Wr) and surface roughness (Ra) of steel disks were investigated via the analysis of variance. It was confirmed that all the three input variables were significant for μ and Wr values, while testing force, nanoparticle concentration and its interaction with testing force and rotational speed were identified as significant parameters for Ra value. According to regression quadratic models, the optimized response values were 0.088, 2.35 × 10-7 mm3·N-1·m-1 and 0.832 μm for μ, Wr and Ra, which were in good agreement with the actual validation experiment values. The tribological results show that 0.20% was the optimum mass concentration which exhibited excellent lubrication performance. Compared to the base fluid, μ, Wr and Ra values had a reduction of approximately 45.6%, 90.3% and 56.0%. Tribochemical reactions occurred during the friction process, and a tribofilm with a thickness of approximately 20 nm was generated on the worn surface, consisting of nanoparticle fragments (rGO and Al2O3) and metal oxides (Fe2O3 and FeO) with self-lubrication properties.

Keywords: lubrication mechanism; nanofluid; reduced graphene oxide; response surface methodology; tribology.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Schematic diagram of the disk-on-disk tribotester and the photo of the pin and disk.
Figure 2
Figure 2
TEM images of (a) rGO, (b) Al2O3 and (c) rGO-Al2O3 nanoparticles.
Figure 3
Figure 3
(a) C 1s, (b) O 1s, (c) Al 2p XPS spectra of the rGO-Al2O3 nanocomposite, and (d) XRD patterns of different nanoparticles.
Figure 4
Figure 4
Normal probability plot of residual for (a) μ, (b) Wr and (c) Ra.
Figure 5
Figure 5
The parity plot illustrating the correlation between actual and predicted values for (a) μ, (b) Wr and (c) Ra.
Figure 6
Figure 6
3D response surface plots showing the interaction effects of different variables on (a–c) μ, (d–f) Wr and (g–i) Ra values.
Figure 7
Figure 7
Tribological behavior of base fluid and rGO-Al2O3 nanofluid: (a) friction coefficient–time curves and (b) wear rate and average friction coefficient.
Figure 8
Figure 8
Surface topography and cross-section depth profile of wear track on the disk lubricated by (a) base fluid and (b) rGO-Al2O3 nanofluid.
Figure 9
Figure 9
SEM micrograph of worn disk surface lubricated with 0.20 wt.% rGO-Al2O3 nanofluid and EDS map scanning results.
Figure 10
Figure 10
(a) TEM image of tribofilm on the worn disk surface, XPS resolved fitting curves of (b) Fe 2p, (c) O 1s and (d) Al 2p spectra of the worn surface lubricated by 0.20 wt.% rGO-Al2O3 nanofluid.
See this image and copyright information in PMC

References

    1. Abellan-Nebot J.V., Rogero M.O. Sustainable Machining of Molds for Tile Industry by Minimum Quantity Lubrication. J. Clean Prod. 2019;240:118082. doi: 10.1016/j.jclepro.2019.118082. - DOI
    1. Bao Y., Sun J., Kong L. Effects of Nano-SiO2 as Water-Based Lubricant Additive on Surface Qualities of Strips after Hot Rolling. Tribol. Int. 2017;114:257–263. doi: 10.1016/j.triboint.2017.04.026. - DOI
    1. Hu C., Ding T., Ou H., Zhao Z. Effect of Tooling Surface on Friction Conditions in Cold Forging of an Aluminum Alloy. Tribol. Int. 2019;131:353–362. doi: 10.1016/j.triboint.2018.11.002. - DOI
    1. Xie H., Dang S., Jiang B., Xiang L., Zhou S., Sheng H., Yang T., Pan F. Tribological Performances of SiO2/Graphene Combinations as Water-Based Lubricant Additives for Magnesium Alloy Rolling. Appl. Surf. Sci. 2019;475:847–856. doi: 10.1016/j.apsusc.2019.01.062. - DOI
    1. Sharma A.K., Tiwari A.K., Dixit A.R., Singh R.K. Measurement of Machining Forces and Surface Roughness in Turning of AISI 304 Steel Using Alumina-MWCNT Hybrid Nanoparticles Enriched Cutting Fluid. Measurement. 2020;150:107078. doi: 10.1016/j.measurement.2019.107078. - DOI