纳米二硫化钨添加剂形态结构与摩擦学性能的构效关系及其在全配方润滑油中的作用机制

Nano tungsten disulfide particles have better heat stability and environmental protection as solid lubricants. It was important to solve dispersion stability of fully formulated lubricants and replacing antiwear or friction-reducing properties of traditional phosphorous and sulfur containing additives for the application of nano additives in environmental protection and energy-saving engine oils. Nano tungsten disulfide additives with different forms and sizes was explored by optimizing synthesis methods, the effects of structure, size, concentration and dispersing technology on dispersion stability and tribological performances were investigated to establish the structure-activity relationships between morphological structure and tribological performances, and reveal the antiwear and friction reducing mechanism of nano tungsten disulfide additives under different friction conditions. The relationship between antiwear properties of nano tungsten disulfide with traditional antiwear and friction reducing additives with compositions and microstructure of protective film formed under different operating conditions were investigated, which was used to illustrate the dynamics of tribofilms growth/removal of the different additive components throughout the mixed and boundary lubrication regimes, and provide lubricating mechanism of nano tungsten disulfide additive instead of traditional additives containing sulfur and phosphorus to form protective lubricant films. Based on this, the dispersion stability and tribological properties of nano tungsten disulfide additives in the formulated lubricating oils were evaluated by several tribological tests, to study the lubrication mechanism of coupling effect between the side surface or lubricants and additives under high-temperature and high-pressure sliding conditons. It can provide theoretical basis and technical support for nano additives improving the energy saving and environmental protection performance of engine oil.

纳米二硫化钨作为具有优良热稳定性和环保性的润滑材料，解决其在全配方润滑油中的分散稳定性和替代传统硫磷添加剂的抗磨减摩性能等关键技术，对于纳米添加剂在环保节能发动机油中推广应用具有重要意义。本项目通过制备出不同形态和大小的纳米二硫化钨添加剂，探索其结构、尺寸、分布、浓度、分散工艺等对其分散稳定性和摩擦性能的影响规律，建立其形态结构与摩擦学性能的构效关系，揭示不同条件下的抗磨减摩作用机理；通过对比研究纳米二硫化钨添加剂与传统抗磨减摩剂在不同工况下形成保护修复膜的组成及微观结构与抗磨、减摩性能之间的关系，建立各添加剂在混合或边界润滑状态下保护膜的生成与破裂动力学机制，揭示其替代传统硫磷添加剂的作用机制；系统考察纳米二硫化钨添加剂在全配方润滑油中的分散稳定性和摩擦润滑性能，探求高温环境下摩擦副表面、润滑油及添加剂之间耦合作用的润滑机理，为纳米添加剂提升发动机油的节能环保性能提供理论依据与技术支撑。

纳米二硫化钨作为性能优良的固体润滑材料，设计制备不同形态结构的纳米WS2添加剂，解决其在润滑油中的分散稳定性，表现出替代传统硫磷添加剂的优良抗磨减摩性能等是本项目的研究目标。主要研究内容和结论如下：.1. 制备了不同形态和尺寸大小的纳米WS2添加剂，并通过吸光值测定等方法，研究了不同形态、尺寸、浓度、分散方法和表面修饰剂等对其在润滑油中分散稳定性的影响规律，发现变幅杆超声分散法以及甲基萘、聚异丁烯丁二酰亚胺和油酸等表面修饰剂，能够有效地提高纳米WS2添加剂在润滑油的分散稳定性，其中球状分散效果最好，其次片状，最后管状。.2. 利用四球摩擦试验机研究了不同形态、尺寸、浓度、表面修饰剂对纳米WS2添加剂在基础油中摩擦性能的影响，通过SEM、EDX和XPS等表面分析手段分析了其抗磨减摩作用机理，发现不同形态、尺寸和浓度的纳米WS2添加剂均不同程度地表现出了较好的抗磨减摩性能，尤其是低含量的纳米WS2润滑效率最高，这种差异性主要受纳米WS2颗粒在油品中的尺寸分布和分散稳定性影响，另外其在摩擦表面的反应活性也会影响。.3. 利用四球摩擦试验机和往复摩擦磨损试验机对比研究纳米WS2与ZDDP 添加剂在不同温度、载荷和摩擦方式下的润滑性能，分析了磨损表面微观结构以及形成保护膜的结构、组成对其抗磨减摩性能的影响，对比探讨了WS2 和ZDDP添加剂的摩擦化学作用机制。发现WS2 添加剂在较宽的温度范围内具有较好的抗磨减摩性能，尤其在高温下表现出了比ZDDP更优异的抗磨损性能，另外纳米WS2与富勒烯碳复配后在基础油中也表现出了良好的抗磨减摩协同效应。.4. 研究了纳米WS2和ZDDP添加剂复配后在宽温度范围的摩擦润滑性能，并考察了WS2 添加剂在全配方润滑油中的物理化学适应性以及对摩擦润滑性能的影响，发现WS2和ZDDP添加剂复配后，在基础油中表现出较好的抗磨减摩协同效应，在全配方润滑油中也能提升其抗磨减摩性能，表现出良好的性能适应性。这为替代和降低发动机油中ZDDP用量，开发高性能润滑油提供了新的技术思路。