Preparation of lanthanum trifluoride nanoparticles surface-capped by tributyl phosphate and evaluation of their tribological properties as lubricant additive in liquid paraffin

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• 作者：Zhiwei Li ; Xiao Hou ; Laigui Yu ; Zhijun Zhang ; Pingyu Zhang
• 关键词：Surface-capped LaF3 nanoparticles ; Lubricant additive ; Preparation ; Tribological properties
• 刊名：Applied Surface Science
• 出版年：15 February, 2014
• 年：2014
• 卷：292
• 期：Complete
• 页码：971-977
• 全文大小：1842 K

文摘

LaF₃ nanoparticles surface-capped by tributyl phosphate (denoted as TBP-LaF₃) were prepared by in situ surface modification route. The size, morphology and phase structure of as-prepared TBP-LaF₃ nanoparticles were analyzed by means of X-ray diffraction and transmission electron microscopy. The thermal stability of as-synthesized TBP-LaF₃ nanoparticles was evaluated based on thermogravimetric analysis, and their tribological properties as additive in liquid paraffin were evaluated with a four-ball friction and wear tester. Moreover, the morphology of worn steel surfaces was analyzed with a scanning electron microscope, and the composition and chemical state of typical elements on worn steel surfaces were examined with an X-ray photoelectron spectroscope. Results show that as-synthesized TBP-LaF₃ nanoparticles possess good thermal stability and excellent anti-wear and load-carrying capacities as well as good friction-reducing ability. This is because, on the one hand, TBP as the surface-modifier is able to improve the dispersibility of LaF₃ nanoparticles in liquid paraffin and allows good adsorption of LaF₃ nanoparticles on sliding steel surfaces. On the other hand, active P element of TBP can form tribochemical reaction film on sliding steel surfaces. As a result, the boundary lubricating film consisting of adsorbed LaF₃ nanoparticles and tribochemical reaction film results in greatly improved friction-reducing and anti-wear abilities as well as load-carrying capacity of the lubricant base stock and gives rise to significantly reduced friction and wear of the steel-steel sliding pair.