Tribological evaluation of PAO 100 oil-based lithium greases with chemically functionalized nanoadditives

IF 1.8 4区工程技术 Q3 ENGINEERING, CHEMICAL

Lubrication Science Pub Date : 2023-05-08 DOI:10.1002/ls.1656

Homender Kumar, Harsha A. P., Sooraj Singh Rawat

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引用次数: 0

Abstract

The lubricating greases employed in this study were formulated with polyalphaolefin (PAO) 100 as the base oil and 12-lithium hydroxystearate as the thickener. The sol–gel method was used to produce the LaF₃ nanoadditives. The oleic acid-treated LaF₃ (i.e., OA-LaF₃) and carboxylic acid-treated MWCNTs (i.e., COOH-MWCNTs) were blended in the formulated grease samples and used as nanoadditives. The detailed microstructural and chemical properties of chemically treated nanoadditives were investigated using HR-TEM, XRD, FTIR and XPS analyses. Using a four-ball tester, the effect of different concentrations of nanoadditives on the tribo-performance of greases was investigated. Tribo-test results revealed the role of nanoadditives in PAO-based grease lubrication performance. COOH-MWCNTs and OA-LaF₃ nanoadditives outperformed PAO grease in terms of physicochemical and tribo-performance for steel-steel tribo-pair. The improved tribo-performance is attributed to the formation of tribo-film on the contact interfaces via nanoadditives. The development of tribo-film was confirmed by XPS analysis of worn surfaces.

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化学功能化纳米添加剂对PAO 100油基锂脂摩擦学性能的影响

以聚α -烯烃(PAO) 100为基础油，羟基硬脂酸锂为增稠剂配制润滑脂。采用溶胶-凝胶法制备了LaF3纳米添加剂。将油酸处理的LaF3(即OA - LaF3)和羧酸处理的MWCNTs(即COOH - MWCNTs)混合在配制的润滑脂样品中，并用作纳米添加剂。采用HR - TEM、XRD、FTIR和XPS等分析手段研究了经化学处理的纳米添加剂的微观结构和化学性能。采用四球测试仪，研究了不同浓度纳米添加剂对润滑脂摩擦性能的影响。摩擦测试结果揭示了纳米添加剂在PAO基润滑脂润滑性能中的作用。COOH - MWCNTs和OA - LaF3纳米添加剂在钢-钢摩擦对的物理化学和摩擦性能方面优于PAO润滑脂。摩擦性能的提高是由于纳米添加剂在接触界面上形成了摩擦膜。磨损表面的XPS分析证实了摩擦膜的形成。

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来源期刊

Lubrication Science ENGINEERING, CHEMICAL-ENGINEERING, MECHANICAL

CiteScore

3.60

自引率

10.50%

发文量

审稿时长

6.8 months

期刊介绍： Lubrication Science is devoted to high-quality research which notably advances fundamental and applied aspects of the science and technology related to lubrication. It publishes research articles, short communications and reviews which demonstrate novelty and cutting edge science in the field, aiming to become a key specialised venue for communicating advances in lubrication research and development. Lubrication is a diverse discipline ranging from lubrication concepts in industrial and automotive engineering, solid-state and gas lubrication, micro & nanolubrication phenomena, to lubrication in biological systems. To investigate these areas the scope of the journal encourages fundamental and application-based studies on: Synthesis, chemistry and the broader development of high-performing and environmentally adapted lubricants and additives. State of the art analytical tools and characterisation of lubricants, lubricated surfaces and interfaces. Solid lubricants, self-lubricating coatings and composites, lubricating nanoparticles. Gas lubrication. Extreme-conditions lubrication. Green-lubrication technology and lubricants. Tribochemistry and tribocorrosion of environment- and lubricant-interface interactions. Modelling of lubrication mechanisms and interface phenomena on different scales: from atomic and molecular to mezzo and structural. Modelling hydrodynamic and thin film lubrication. All lubrication related aspects of nanotribology. Surface-lubricant interface interactions and phenomena: wetting, adhesion and adsorption. Bio-lubrication, bio-lubricants and lubricated biological systems. Other novel and cutting-edge aspects of lubrication in all lubrication regimes.