中文摘要：

MnZnFe2O4纳米磁性颗粒由于同时具备磁性和纳米尺寸,作为润滑油添加剂会对纳米级油膜的润滑特性和成膜机理有极大的影响。采用共沉淀法制备MnZnFe2O4纳米磁性颗粒,对其粒径分布和磁性能进行检测,加入基础油中获取分布均匀的润滑油,检测润滑油粘度。同时采用纳米膜厚测量仪,研究不同质量分数下纳米磁性颗粒对于薄膜润滑性能的影响。研究表明,不同质量分数对润滑油粘度影响不同,且润滑油在不同卷吸速度下的膜厚、中心膜厚形态、流动性与粘度无关,而与质量分数直接相关。指出油酸包覆的纳米磁性颗粒之间存在决定分散和团聚的极限间距,当润滑间隙减小到磁力矩作用范围时,在分子作用力、附加磁力矩共同作用下,磁性颗粒和润滑油分子共同形成吸附层,并达到有序排列,形成强度更高的、更稳定、更厚的薄膜润滑。

英文摘要：

MnZnFe2O4 nano-magnetic particles have both magnetic properties and nano-size which will have a significant impact on the resulting film properties and forming mechanism as lubricant additives.MnZnFe2O4 magnetic nanoparticlesare are prepared by the coprecipitation method.Their size distribution and magnetic properties are tested.MnZnFe2O4 magnetic nanoparticles can be directly added into base oil to obtain lubricant oil.Viscosity of lubricating oil is detected.At the same time,the effects of different mass fraction on the thin film lubrication performance are studied with nano-film thickness measuring instrument.Studies show that lubricant viscosity is affected by different mass fraction differently.Under the different entrainment speeds,film thickness,center thickness patterns,liquidity and viscosity are affected by mass fraction directly,but has nothing to do with its viscosity.Then it is pointed out：when distance between MnZnFe2O4 magnetic particles is smaller to some value,weak magnetic-moment will be formed among magnetic particles,magnetic particles and the metal surface.It makes part of the adjacent magnetic particles form a dynamic aggregation,some magnetic particles are adsorbed on the metal surface,which contribute to form a higher strength,more stable and thicker physical adsorbed film.