纳米级水基润滑中的水合效应与双电层效应研究

Air pollution and environmental deterioration have become the serious problems people have to face. The energy consumption per unit GDP of China is 4.7 times of that of Germany (2.2 times of the average level of the world), although both of the two counties are super country in manufacture industry. 1/3 primary energy in the world are consumed by friction, and 80% devices are out of work due to wear. Decreasing energy consumption and developing environment-friendly technique have become the big challenge for tribology researchers. Water based lubrication is one of the solutions for such challenge due to advantages of water, such as environmental friendliness, abundant resources, and super low friction. However, there are some shortages of water lubrication, such as low viscosity, poor film forming capability, and corrosion for metal, etc. In water based lubrication, the space between two surfaces of friction pairs is in the scale of nano meter, and lubrication mode is boundary lubrication or thin film lubrication. The key factor of the application of water based lubricant is to increase the carrying capacity of water film in nano spaces. In this project, the research will start with the double layer effect and hydration effect in nano space. Methods, such as synthesis of additives with special functional groups and surface modification of the friction pair, will be performed to increase the repulsion between the surfaces in nano space. The relationship between the lubrication properties of water based lubricant and the long range and short range interaction between molecules. By this method, a bridge between the macro tribological properties and the nano mechanical and nano tribological properties will be established. Based on the basic researches, the water based lubricants for some special application purposes will be developed. The application possibility of water based lubrication will be studied.

空气污染、环境恶化已成为我们面临的严峻问题。同为制造大国，我国的单位GDP能耗是德国的4.5倍，是世界平均水平的2.2倍。一次性能源的1/3消耗于摩擦，80%的装备由于磨损失效。降低能耗、发展环境友好技术，是摩擦学界面临的巨大挑战。水基润滑是解决该问题的重要途径之一。其具有环境友好、资源丰富，超低摩擦等优点。但同时具有粘度低，成膜能力差，易腐蚀等缺点。水基润滑条件下，摩擦副的间距为纳米量级，处于边界润滑或薄膜润滑状态。如何提高纳米间隙下水基润滑膜的承载能力，成为水基润滑能否广泛应用的关键。本项目从微观入手，研究纳米间隙下的水合效应和双电层效应。通过合成带有特定功能基团的添加剂以及摩擦副表面改性，增强纳米尺度下表面间的相互斥力。同时研究这种分子间的长程和短程作用力与水基润滑剂宏观摩擦学性能间的关系，建立起纳米力学、摩擦学性能和宏观摩擦学性能间的联系桥梁，开发出具有广泛应用前景的水基润滑技术。

本项目针对水介质中两相互接触表面间的水合力和双电层力开展研究，研究其在水基超滑和水基润滑中的作用。并对多种水基润滑体系的润滑特性以及水基润滑的应用进行了研究。.（1）研究了表面间距与水合力之间的关系，表明离子水合层承受较大的外部载荷。研究了受限条件下水合层的剪切特性，表明水合层之间的剪切力非常小，因而可以实现超滑，并首次实验测得了水合层的等效粘度。利用水合作用，使用带有阳离子端头的表面活性剂分子修饰水溶液，在AFM上实现了超滑，并揭示了微观尺度下水合基团的超滑规律和机理。通过酸预跑合，利用水合碱金属离子实现了宏观接触和实验条件下水基超滑。.（2）通过氢离子诱导实现了油基超滑。氢离子会诱导Si3N4表面发生摩擦化学反应，是摩擦副表面形成微平面，只要使润滑剂的粘度和摩擦副的相对滑移速度满足一定的条件，即可实现超滑。提出了摩擦系数与润滑剂粘压系数（α）和接触压力（p）之间的关系式，解释了实现超滑的条件。.（3）建立了和频光谱监测系统，用于观测固液界面处谁分子的结构和取向，实现摩擦副界面和频光谱的在线检测。.（4）研究了水滑石纳米片、PAG聚醚、海藻酸钠、羟乙基纤维素、魔芋葡甘聚糖多种水溶液的润滑特性。发现水滑石纳米片可有效地减少磨损。而其它几种高分子水溶液均可在一定条件下实现超滑。.（5）基于前述研究，以金属加工润滑为应用背景，进行了水基润滑的应用研究。通过合理的设计润滑剂的体系，增强润滑分子与表面的相互作用，针对钛合金、铝合金等难加工金属，开发出具有低摩擦性能的水基金属切削液。另外，还开发出可降低轧制力的钢板冷轧润滑液。.本课题研究过程中共发表相关论文46篇，其中38篇被SCI检索。申请专利28项。项目组成员在国际和国内会议上做邀请报告11次。项目负责人获国家自然科学奖二等奖1项。培养博士研究生7人，其中6人已经毕业。