Preparation and tribological properties of oleic acid-decorated MoS₂ nanosheets with good oil dispersion

Abstract

In this paper, the self-made two-dimensional MoS₂ nanosheets with five-layer thickness were attempted to be modified with oleic acid (OA) with a simple one-step route, denoted OA-MoS₂. The OA-MoS₂ nanosheets were confirmed by a series of characterizations. The results showed that OA molecules could chemically seal MoS₂ nanosheets through C-S bonds, which significantly improved the dispersibility and stability of MoS₂ nanosheets in base oil. The OA-MoS₂ nanosheets possessed better dispersibility in base oil and could maintain the stability in oil up to 96 h. Furthermore, the tribological properties of OA-MoS₂ nanosheets as an additive in base oil were completely studied through a ball-on-ball configuration four-ball testing machine. The experimental results showed that the average friction coefficient and average wear scar diameter of the 0.04 wt.% OA-MoS₂-based oil were decreased by about 41.2% and 17.1% as compared to base oil, respectively. In addition, its extreme pressure performance increased by about 13.0%. These results indicated that OA-MoS₂ nanosheets exhibited better antifriction, antiwear and extreme pressure abilities in oil due to the desirable solved dispersibility.

Graphical Abstract

Keywords:

• Dispersibility
• MoS2
• nanosheets
• oleic acid
• tribological properties

Acknowledgements

This work was supported by the Talent Introduction Fund of Yangzhou University (2012), Key Research Project-Industry Foresight and General Key Technology of Yangzhou (YZ2015020), Innovative Talent Program of Green Yang Golden Phoenix (yzlyjfjh2015CX073), Yangzhou Social Development Project (YZ2016072), Jiangsu Province Six Talent Peaks Project (2014-XCL-013), Jiangsu Province Science and Technology Support Project (BE2014613) and Jiangsu Industrial-academic-research Prospective Joint Project ( BY2016069-02). The authors also acknowledge the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions. The data of this paper originated from the Test Center of Yangzhou University.