【作者】 李文静；

【导师】 查飞； 王金清；

【作者基本信息】 西北师范大学 ， 工程硕士（专业学位）， 2020， 硕士

【摘要】 稀土元素以其独特的4f电子结构和物理化学性质被广泛应用于多个领域。在润滑领域,稀土类化合物的引入可大幅提升润滑油或固体润滑薄膜的承载力和抗磨损性能。然而,作为润滑油添加剂,稀土在润滑油中的分散性成为亟待解决的问题。还原氧化石墨烯（RGO）独特的层状结构和低剪切力使之具有成为理想润滑材料的潜质。然而,由于层间范德华力的存在,RGO片层易于团聚,阻碍了实际应用。稀土有机配合物是一种性能优良的油溶性极压抗磨添加剂,根据“相似相容”原理,选择具有大π结构的1,10-菲啰啉（Phen）作为第一配体,具有长碳链结构的弱极性油酸（OA）作为第二配体合成极性较弱、亲油性好的稀土有机三元配合物,然后和还原氧化石墨烯复合,围绕稀土有机配合物复合材料的结构设计及摩擦学性能表征展开研究,主要研究内容如下:1.采用一锅法制备了含Phen和OA两种配体的铈有机三元配合物Ce（Phen）（OA）₃。通过红外、紫外、核磁及热重对其组成和结构进行了表征,利用SRV-IV型微动摩擦磨损试验机考察了添加不同浓度目标产物的润滑油的摩擦学性能。发现相比于只有一种配体的配合物,稀土有机配合物Ce（Phen）（OA）₃在基础油PAO8中的分散稳定性得到了改善,基础油的寿命得以提升,少量（0.1%）添加即可使极压性能提高67%,磨损体积/磨损率减小98%。2.采用一锅法制备了铕有机三元配合物Eu（Phen）（OA）₃。结果表明,Eu（Phen）（OA）₃和Ce（Phen）（OA）₃两种物质结构相似。添加Eu（Phen）（OA）₃的基础油的寿命长于添加Ce（Phen）（OA）₃。Eu（Phen）（OA）₃非常少量（0.06%）的添加即可使极压性比基础油提高150%,添加Eu（Phen）（OA）₃的磨损体积比基础油减少93%;此外,添加Eu（Phen）（OA）₃的磨损体积占添加Ce（Phen）（OA）₃的约24%。3.通过水热法调节GO胶态悬浮液前驱体的比例,合成了均匀分散的铕-1,10-菲啰啉-油酸/石墨烯复合材料RGO/Eu（Phen）（OA）₃（RGECs）。RGECs既包含石墨烯的润滑性能,又拥有Eu（Phen）（OA）₃优异的抗磨损性能。Eu（Phen）（OA）₃不仅能抗磨损,还能起到隔离作用,防止石墨烯纳米片重新堆叠;同样,石墨烯纳米片为Eu（Phen）（OA）₃的负载提供了一个良好的载体。制备的RGECs在基础油PAO8中具有良好的分散稳定性,摩擦系数并无明显变化,然而基础油的寿命大大延长,并且优于商用添加剂二烷基二硫代磷酸锌（ZDDP）;同时,添加适量（0.08%）的RGECs使钢球上的磨斑面积减少约56%,磨损体积/磨损率较之ZDDP减少约37%,说明抗磨损性能增强。更多还原

【Abstract】 Rare earth elements are widely used in many fields due to their unique 4f electronic structure and physical and chemical properties.In the field of lubrication,it has been proved that the introduction of rare earth compounds can greatly improve the hold-bearing capacity and wear resistance of lubricating oil or solid lubricating film.However,as a kind of additive of lubricating oil,the dispersity of rare earth in lubricating oil has become an urgent problem to be solved.The unique layered structure and low shear force of educed graphene oxide（RGO）make it an ideal lubricating material.However,due to the existence of van der Waals force between layers,RGO layers are easy to agglomerate,which hinders the practical application.Rare earth organic complex is an oil soluble extreme pressure antiwear additive with excellent properties.As a common ligand,unique largeπ-conjugated structure of 1,10-phenanthroline（Phen）contributes to the adsorption on friction interface.Additionally,the longer carbon chain structure and weaker polarity of oleic acid（OA）are similar to those of base oil.Therefore,oleic acid is selected as the second ligand on the principle of the dissolution in the similar material structure.Then,it was compounded with RGO to study the structure design and tribological properties of rare earth organic complex composite.The main research contents are as follows:1.Ce（Phen）（OA）₃,an organic ternary complex,was prepared by one pot method.The composition and structure of the complex were characterized by FTIR,UV,NMR and TGA.The tribological properties of lubricating oil with different concentrations of target products were investigated by SRV-Ⅳfretting friction and wear tester.It is found that the dispersion stability of Ce（Phen）（OA）₃ in base oil is improved,and the life of base oil is extended.A small amount（0.1%）of Ce（Phen）（OA）₃ could improve the extreme pressure by 67%,and the wear volume/wear rate decreased by 98%2.Eu（Phen）（OA）₃ was prepared by one pot method.The results show that the structures of Eu（Phen）（OA）₃ and Ce（Phen）（OA）₃ are similar.The life of base oil with Eu（Phen）（OA）₃ is longer than that with Ce（Phen）（OA）₃.A very small amount of Eu（Phen）（OA）₃（0.06%）is able to increase the extreme pressure by 150%compared with the base oil and the wear volume with Eu（Phen）（OA）₃ is 93%lower than that with Ce（Phen）（OA）₃.In addition,the wear volume with Eu（Phen）（OA）₃ accounts for about24%of that with Ce（Phen）（OA）₃.3.RGO/Eu（Phen）（OA）₃（RGECs）composites were successfully synthesized by simple hydrothermal method.The ratio of precursor of GO colloidal suspension can be adjusted at the same time.RGECs not only contains the lubricity of graphene,but also has excellent wear resistance of that of Eu（Phen）（OA）₃.In particular,Eu（Phen）（OA）₃can not only resist wear,but also play a role in isolation and prevent graphene nanosheets from re-stacking.In the same way,graphene nanosheets provide a good support for Eu（Phen）（OA）₃,and the prepared RGECs have good dispersion stability in the base oil.The friction coefficient has no obvious change,however,the service life of the base oil is greatly improved,which is better than the commercial additive ZDDP.At the same time,adding appropriate amount（0.08%）of RGECs can reduce the wear spot area by about 56%,the wear volume/wear rate by about 37%compared with ZDDP,which indicates that the wear resistance is enhanced.更多还原