含纳米高铼酸盐/石墨烯添加剂油品宽温域混杂润滑效应研究

Designing and preparing continuous lubricating materials over a wide temperature range are challenges for high-technology industry field. The single kind of lubricating material performs only within a narrow temperature range, which is difficult to satisfy the continuous lubrication demand in a wide temperature range. Therefore, the combination of multiple lubricants is one of effective way to realize the continuous lubrication over a wide temperature range. This project aims to synthesize a series of nano-perrhenates through hydrothermal synthesis method, and then the liquid ultrasonic stripping method is utilized to combine nano-perrhenate and graphene. The synthesized nano-perrhenate/graphene is dispersed into lubricating oil as additives via surface modification. Then, we plan to investigate the tribological properties of oil containing nano-perrhenate/graphene additive from room temperature to 800°C under atmospheric condition. By virtue of the testing technology, the influencing mechanisms of preparation process parameters on the morphology and microstructure of the nano-particles will be analyzed; a detail investigation of nano-particles’ surface structure and potential associated with surface modifiers and dispersing technology will be explored; the friction-reducing mechanisms and synergistic effects of hybrid lubricating system at different temperature sections will be examined; comparative study on how the nano-perrhenate/graphene influences the thermostability and oxidation product content of base oil under static-state temperature rising environment and simulated tribological conditions will be thoroughly carried out, which will provide theoretical basis for the prediction of the hybrid lubricating system’s properties in friction reduction and the analysis of their failure mechanisms during a wide temperature range.

设计制备宽温域范围具有良好摩擦学性能的润滑材料是尖端工业领域迫切解决的难题。单一品种润滑材料难以满足宽温域连续润滑的要求，因此合理运用多种润滑材料的协同润滑效应是实现宽温域连续润滑的有效方法。本项目拟采用水热合成法制备系列纳米高铼酸盐，利用液相超声剥离法将纳米高铼酸盐与石墨烯复合，并通过表面修饰技术将其分散到润滑油中，考察含纳米高铼酸盐/石墨烯添加剂油品大气环境下室温至800°C宽温域摩擦学行为。结合分析测试技术，研究制备工艺参数对纳米高铼酸盐及纳米高铼酸盐/石墨烯复合物的形貌及晶体结构的影响机制；构建表面改性剂及分散工艺参数与纳米添加剂表面结构及电势的关联；揭示混杂润滑体系在不同温度区间的减摩机理及协同效应；对比研究纳米高铼酸盐/石墨烯在静态单纯升温与模拟摩擦工况条件下对基础油的热稳定性和氧化产物含量的影响规律，为该类混杂润滑体系宽温域减摩性能预测与失效机制分析提供理论依据。

随着高端装备性能不断提高，其运行工况愈发苛刻，运动部件长期处于高温及频繁启停的状态中。设计制备宽温域范围具有良好摩擦学性能的润滑材料是尖端工业领域迫切解决的难题。然而，单一品种的润滑材料工作温度区间窄，难以满足宽温域连续润滑的要求，合理运用润滑组分在不同温域工况的润滑效应、响应特性、协同作用是实现宽温域连续润滑的有效方法。基于此，本项目采用化学方法制备系列纳米高铼酸盐，利用液相超声剥离法将纳米高铼酸盐与石墨烯复合，并通过表面修饰技术将其分散到基础润滑油中，考察含纳米高铼酸盐/石墨烯添加剂油品大气环境下宽温域摩擦学行为及使役性能。研究发现，化学合成方法制备的纳米高铼酸盐具有晶体形态，尺寸约为20nm，粒径均匀，并通过调整超声工艺参数可使高铼酸盐均匀负载在石墨烯表面。采用表面活性剂及离子液体对复合添加剂进行表面修饰，使复合添加剂表面含有长链或苯环等亲油基团并改变其表面电势，可形成添加剂间的空间位阻效应并提高复合添加剂的Zeta电位绝对值，使其稳定的分散在基础油中达到60天以上。宽温域摩擦学测试表明，含纳米高铼酸盐/石墨烯添加剂在较低温度区间可有效提高基础油的抗磨减摩性能，并且石墨烯良好的导热性能可使接触界面热传递方向发生改变。随着温度升高，纳米高铼酸盐/石墨烯添加剂在摩擦诱导作用下与摩擦副材料发生复杂的摩擦化学反应形成由合金自生氧化物、碳化物及高铼酸盐构成的保护层，有效的缓解了摩擦副间的直接接触，600°C时平均摩擦系数约为0.2。纳米高铼酸盐/石墨烯的引入并未影响基础油的热稳定性及抗氧化性，对比于纯基础油，复合添加剂可有效减少基础油氧化分解产物的含量，这归因于高温摩擦过程基础油氧化产物与复合添加剂及金属组分发生反应形成复杂的碳化物及其衍生物。本项目的研究成果有望为含纳米高铼酸盐/石墨烯添加剂润滑油品在苛刻摩擦工况下的减摩性能的预测评价及润滑失效机制的分析提供重要的实验理论依据。