Understanding the tribological impacts of alkali element on lubrication of binary borate melt |
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| Authors: | Bach H Tran Kiet Tieu Shanhong Wan Hongtao Zhu Shaogang Cui Liping Wang |
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| Institution: | Faculty of Engineering and Information Sciences, University of Wollongong, Northfields Avenue, Wollongong NSW 2522 Australia.; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 China |
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| Abstract: | Melt lubricants have been regarded as an effective class to deliver lubrication on moving mechanical contacts at extreme temperatures. Among the elementary constituents, alkali elements play a critical role in governing the physical–chemical characteristics of the lubricant despite the obscurity regarding their intrinsic roles on the rubbing interfaces. The present study attempts to unfold the effects of sodium on the tribological responses of mating steel pair under borate melt lubrication. It has been found that the involvement of Na inspires a total reversal in lubricating potentials of the lone B2O3 melt manifested by remarkable friction reduction, wear inhibition and prolonged load-bearing capacity. These exceptional performances are attributed to the accretion of nanothin Na layers on the contact interfaces. The interfacial occurrences are interpreted from a physico-chemistry perspective while the influences of surface microstructure are also discussed in detail. Multiple characterizations are employed to thoroughly examine the sliding interfaces in multi-dimensions including Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM) and Atomic Force Microscopy (AFM). In addition, chemical fingerprints of relevant elements are determined by Energy Dispersive Spectroscopy (EDS) and Electron Loss Energy Spectroscopy (EELS).The involvement of sodium induces dramatic transformation in lubrication potentials of boron oxide melt. |
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