An investigation on the lubrication effectiveness of MoS2 and BN layered materials as oil additives using block-on-ring tests. (November 2020)

• Record Type: Journal Article
• Authors: Wu, Hongxing; Yin, Shaochong; Du, Yin; Wang, Liping; Wang, Haifeng
• Is Part Of: Tribology international. Volume 151(2020)
• Publication Date: 2020-11
• Subjects: Layered materials -- BN and MoS2 -- Lubrication effectiveness -- Depositing tribofilm mechanism; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2020.106516
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: The commonly accepted interlayer shear mechanism for layered materials as oil additives remains a challenge with the emergence of two-dimensional materials. In this work, the lubrication effectiveness of MoS2 and BN nanosheets with a similar size was investigated as oil additives using block-on-ring tests. BN nanosheets reveal remarkable anti-wear performance and a reduction of wear depth of about 50%, whereas, the expected friction and wear reduction were not found for MoS2 nanosheets. X-ray photoelectron spectroscopy (XPS) investigation indicates the generation of boron-based tribofilm for BN nanosheets and MoS2 -complex tribofilm for MoS2 nanosheets. Together with the thermal stability analysis, we found that it is the high strength tribofilm with high oxidation resistance, but not the layer structure, that plays a critical role in lubrication enhancement. This study highlights the advance of 'depositing tribofilm' mechanism in novel additive design. Graphical abstract: Image 1 Highlights: Layered materials with similar size and shape were selected. Expected friction and wear reduction was not found for MoS2 nanosheets in this study. BN nanosheets reveal the remarkable anti-wear property with strong tribofilm strength. It is a challenge to explain the results by using interlayer shear mechanism. Depositing tribofilm mechanism would be preferable for novel particle additive design.