WS2的长程有序定向组装及其复合材料的润滑特性研究

The anisotropic crystal structure of WS2 and the disorder distribusion in its composites, resulted the lubricating property loss. This problem can be solved by building the composites with special microstructure which have the long-range order lamellar structure WS2 scaffold. This scaffold can be built through the bidirectional-gradient temperature field gelatin freeze casting. The research will reveal the influencing regularity of cross-linked structure generated by the gelatin and slurry rheological properties of heavy particles. Besides, the assembly behavior of WS2 nano-flakes and the mechanism for controlling the order degree will be surveyed. Further, the lubricating behavior of Ag-Cu/WS2 with the ordered distribution lubricant phase and the rule of WS2 distribution on the electric contact property in vacuum will be analyzed. This study provides an in-depth investigation into the building or destroying of tribo-film which can be attributed to many factors, such as the oriented distribution parameters, the degree of order, the relationship of orientation, and so on. Therefore, the design parameter of material microstructure with the good service stability in high orbit space can be obtained. The design theory and preparation method of sliding electrical contact material with the controlled lubricating property will be achieved.

针对固体润滑剂晶体结构的各向异性及其粒子在复合材料中无序分布特征所导致的润滑性能取向性损失问题，采用双向梯度温场-胶体冰模板技术构建长程有序WS2定向组装骨架，并据此获得润滑相具有宏、微观双尺度定向分布特征的Ag-Cu/WS2复合材料。研究将揭示明胶的交联结构对重质颗粒的稳固作用以及浆料流变性能的影响规律；探明双向梯度温场作用下，片状WS2颗粒的组装行为及其畴域有序度控制机理；掌握固体润滑相定向分布参数、有序畴尺度、取向关系等因素对其复合材料润滑膜成膜/消耗行为、滑动电接触性能的影响机制；获得具有高空间服役稳定性的材料微结构设计参数，发展并建立润滑性能可控型空间滑动电接触材料设计理论和制备方法，提升空间滑动电接触材料的服役稳定性。

金属基固体自润滑复合材料在节能、节材、降耗、减排等方面作用显著。而作为典型的层状粒子，固体润滑剂的润滑具有典型的各向异性，其粒子在复合材料中无序分布特征可导致润滑性能损失。因此，实现固体润滑剂定向排列有望获得摩擦磨损性能优异的自润滑复合材料。本研究以具有六方片层状结构WS2固体润滑颗粒为研究对象，采用冰晶模板法对其定向排列组装，探明了冷冻方式和浆料流变性对多孔WS2支架微观结构的调控机理及影响规律，获得了具有长程有序且颗粒择优取向的层状多孔WS2支架，系统分析了多孔WS2材料的颗粒择优取向性和孔径分布；以层状多孔WS2支架为基础，通过真空浸渗法制备了层状结构特性的Cu-WS2复合材料，阐明了该材料中WS2润滑相转移至摩擦界面处的演变规律；此外，开发了复合冰晶模板法制备WS2定向排列的Cu-WS2、Ag-WS2复合材料的工艺技术，与传统粉末冶金工艺制备的Cu-WS2复合材料相比，WS2定向排列使得该材料的摩擦系数和磨损率分别降低了17%和49%。本研究为新一代空间滑动电接触材料微观结构设计提供理论指导和方法基础，具有重要的学术价值和应用前景。