脲基功能化的咪唑无卤素离子液体对复合锂基润滑脂摩擦学性能的影响

合成了两种脲基功能化的咪唑无卤素离子液体DOSS-1和DOSS-4. 采用SRV-V微动摩擦磨损试验机和Bruker-NPFLEX表面非接触光学三维轮廓仪，考察这两种离子液体作为2号复合锂基润滑脂(G)的减摩抗磨添加剂的摩擦学性能. 摩擦测试结果表明:这两种功能化咪唑离子液体添加到2号复合锂基润滑脂(G)中均表现出优异的减摩抗磨性能. 在添加量同等条件下，长链的DOSS-4表现出优于DOSS-1的减摩抗磨性能. 当添加质量分数为3%时，DOSS-4和DOSS-1的减摩抗磨性能最佳. 利用表面轮廓和扫描电镜进一步分析了磨斑表面的形貌，同时结合X射线光电子能谱仪(XPS)进一步分析了磨斑表面主要化学元素组成，阐明其摩擦机理. 该离子液体能够显著地降低摩擦磨损是因其在摩擦副表面形成了含N元素和S元素的化学反应膜. 

Effect of Urea-Containing Imidazole Halogen-Free Ionic Liquid on Tribological Properties of Composite Lithium Grease

Two urea based-functionalized imidazole halogen-free ionic liquids (IL), DOSS-1 and DOSS-4 were synthesized. As reduce friction and anti-wear additives for 2# lithium complex grease (G), their tribological properties were investigated using friction and wear tester (SRV-V) and surface non-contact optical 3D profiler (Bruker-NPFLEX). The friction test results show that lithium complex grease with addition of ILs had excellent friction-reduction and anti-wear performance. The addition of 3% DOSS-4 (or DOSS-1) produced excellent improvement for friction and wear. The tribological property of DOSS-4-G is superior to DOSS-1-G of equivalent addition amount of IL. The surface morphology of the worn surface was analyzed by a Bruker-NPFLEX 3D surface profile and scanning electron microscopy. The chemical states of the main elements of wear spot was determined by X-ray photoelectron spectroscopy and the lubrication mechanism was clarified. The significant effects for IL on the friction-reduction and anti-wear performances were attributed to the formation of tribofilm containing elements N and S on the worn surfaces.