ISSN   1004-0595

CN  62-1224/O4

高级检索

原位表面修饰活性氧化铈纳米微粒的制备和摩擦学性能研究

Preparation of In-Situ Surface-Capped Active Cerium Oxide Nanoparticles and Evaluation of Their Tribological Properties

  • 摘要: 使用纳米润滑油添加剂是控制摩擦磨损最有效的方法之一,对节能减排和环境保护具有重要意义. CeO2纳米微粒作为润滑油添加剂不仅能降低摩擦磨损,对磨损部位还具有修复作用,从而提高机械部件的使用寿命和安全性. 但CeO2纳米微粒作为润滑油添加剂时的分散稳定性及极压性能有待进一步提高. 鉴于此,本文中中分别以异辛酸和异辛酸/己二酸作为修饰剂,利用原位表面修饰方法制备了表面修饰的CeO2纳米微粒;表征了2种CeO2纳米微粒的结构、热稳定性和表面修饰量等;测试了其在AN5基础油中的减摩抗磨性能和极压性能,分析了其摩擦学机理,并探讨了不同修饰剂对CeO2纳米微粒在摩擦副接触表面成膜能力的影响. 结果表明,所制备的原位表面修饰活性CeO2纳米微粒具有良好的摩擦成膜能力,可有效地提高润滑油的减摩抗磨能力和极压性能.

     

    Abstract: In modern industry, the friction parts of mechanical equipment are faced with more demanding conditions, such as higher loads, higher operating speeds, longer operating cycles, higher temperatures, greater temperature differences and more frequent starts and stops, which causes a large loss of energy. Using nanoscale lubricating oil additives is one of the most effective ways to control friction and wear, which is of great significance for energy saving, emission reduction and environmental protection. As a lubricant additive, CeO2 nanoparticles can not only reduce friction and wear, but also can repair worn area, thereby adding to the service life and safety of mechanical devices. However, CeO2 nanoparticle exhibits poor friction activity and extreme pressure properties. Therefore, 2-ethylhexanoic acid (EHA) and adipic acid (AA) were selected as the modifiers to prepare surface-capped CeO2 nanoparticles by in-situ surface modification method. The structures of the as-prepared EHA-capped and EHA/AA-capped CeO2 nanoparticles were characterized. Their friction-reducing and antiwear abilities as well as extreme pressure properties in AN5 base oil were evaluated, and their tribomechanisms were analyzed. Furthermore, the effect of the surface modifiers on the film-forming ability of the EHA-capped and EHA/AA-capped CeO2 nanoparticles upon rubbing was discussed. Quartz crystal microbalance (QCM-D) tested the adsorption behavior of EHA-capped and EHA/AA-capped CeO2 nanoparticles. Results indicated that the CeO2 nanoparticles had uniform particle size of 2 nm, and AA andEHA/AA were successfully modified on the surface of CeO2 nanoparticles. The as-prepared EHA-capped and EHA/AA-capped CeO2 nanoparticles could be uniformly dispersed in the AN5 base oil and maintained for 90 days without settling. Tribological performance test showed the as-prepared EHA-capped and EHA/AA-capped CeO2 nanoparticles exhibited good film-forming ability during sliding and could effectively improve the friction-reducing and antiwear abilities as well as extreme pressure properties of the base stock. The results of QCM-D showed that EHA/AA-capped CeO2 nanoparticles could be adsorbed on metal surface faster and with larger adsorption thickness. In addition, EHA/AA-capped CeO2 nanoparticles had better anti-wear properties, due to the carboxyl active groups contained in the surface modifier, EHA/AA-capped CeO2 nanoparticles were more easily adsorbed and deposited on the metal surface, so that they could be adsorbed and deposited on the friction surface more quickly, forming a more denser and thicker adsorption layer to protect the friction surface. As the friction progresses, cerium oxide nanoparticles participated in the tribochemical reaction to form a nanocomposite lubrication film.

     

/

返回文章
返回