磷酸酯类双离子液体的合成及摩擦学性能研究

Tribological Behavior of the Ionic Liquid of 1,1′-(hexane-1,6-diyl)bis (3-ethyl-1H-imidazolium-1-yl) Diphosphonate as a Lubricant

以咪唑、1,6-二溴代己烷和磷酸三乙酯合成1,6-二(3-乙基-1-咪唑基)己烷二乙基磷酸盐双离子液体,采用核磁共振谱仪(NMR)和傅立叶变换红外光谱仪(FTIR)等对其结构及理化性能进行了分析;用SRV摩擦磨损试验机考察了其作为钢/钢体系润滑剂的减摩抗磨作用;用SEM和XPS对磨痕表面的形貌和元素组成进行了表征,并分析了其润滑机制.结果表明,该类双离子液体具有较好的低温流动性,作为润滑剂对钢/钢摩擦副具有优异的减摩抗磨性能.XPS分析结果表明,该离子液体在钢磨损表面形成了含FePO4和Fe4(P2O7)3等物质的边界润滑膜,从而有效地提高了摩擦副的承载能力和抗磨损性能.

The dicationic ionic liquid of 1,1＇ - （hexane - 1,6 - diyl） bis （3 - ethyl - 1 H - imidazolium - 1 - yl） diphosphonate was prepared and characterized by FT - IR and 1 H - NMR. The viscosity and density of the synthetic DIL were measured. Tribological properties of this dicationic ionic liquid as a new kind of promising lubricant for a steel/steel contact were investigated on an Optimal SRV friction and wear tester. The morphology and element analysis of the worn scar surface were characterized by scanning electron microscopy （SEM） and x- ray photoelectron spectroscopy （XPS）, respectively. The lubricating mechanism of the ionic liquid was proposed. The experimental data showed that this dicationic ionic liquid possessed some advantages, e.g. relatively high viscosity index and low pour point. And the synthetic dicationic ionic liquid showed excellent tribological behavior and was superior to PAO4 in terms of friction - reduction and load - carrying capacity. A boundary lubricating film of ionic liquid was formed on the steel worn surface by physical adsorption, while tribochemical reaction of the ionic liquid with the steel surface was involved at an elevated temperature to generate a boundary lubricating film containing FePO4 and Fe4 （ P2 O7 ） 3. This contributed to reduced friction and wear.