近年来，人类为了避免不必要的摩擦所造成的损失，不断地探索并优化着新的润滑材料和方法。二维材料由于其独特的晶体结构以及理化特性从而成为摩擦学领域研究的热点之一。由于其在化学组成、粒径尺寸和微观形貌等方面的多样性和可控性，因此值得在摩擦学领域的实际应用与机理分析方面展开深入的探究。针对此类材料的上述特点，本文选取水滑石层状材料为研究对象，在尺寸、形貌、化学组成等多方面对其进行调控，并添加到不同的润滑介质中，展开摩擦学特性研究。首先，以共沉淀法为基础，通过调控反应过程中的实验条件和反应物原料，制备得到不同微观形貌以及化学组成的水滑石纳米材料。利用机械滚压搅拌的方法将上述所合成的材料分散到基础脂中。在同等实验条件下，通过比较几种不同微观形貌或化学组成的水滑石添加剂摩擦学性能，发现在基础脂中添加形貌较为疏松的样品能够更加有效地提升摩擦磨损性能。此外，镍铝组分相比于其它化学组成的水滑石样品更能起到良好的润滑效果。随后，以反相微乳液法为基础，通过控制水热反应过程的时间制备得到了三种尺寸大小不同但结构和形貌相近的纳米水滑石薄片。将三种样品均匀分散在基础油中并进行摩擦实验。在常规工况条件下，基础油中添加少量纳米水滑石薄片后，摩擦磨损性能均可得到改善。在摩擦滑动过程中，相对较大尺寸的样品由于其自身良好的晶体结构形成了力学性能良好且质地均匀的润滑反应膜，展现出了最优异且稳定的摩擦学性能。接着，将表面修饰过的纳米水滑石片以一定质量比例加入到水中，得到稳定半透明的悬浮液。在较高的接触压强下，对该悬浮液以及常见的水基润滑液进行摩擦实验，发现纳米水滑石片作为水基添加剂能够明显改善减摩和抗磨性能。通过改变悬浮液中添加剂的质量分数以及摩擦过程中的相对运动速度，进一步阐明了该添加剂的适用范围。最后，在发现了聚醚水溶液超滑现象的基础上，探究了超薄纳米水滑石片的加入对该超滑体系的影响。在跑合阶段，引入的水滑石片使得摩擦副表面能够更快地得到平坦化以及抛光，并且对接触区内的流体连续性以及水合层之间的剪切作用产生显著影响。因此，不仅缩短实现超滑的跑合过程，而且提高了承载能力。
In recent years, new lubricant materials and methods have been constantly explored and optimized in order to avoid unnecessary friction. Due to its unique crystal structure and physicochemical properties, two-dimensional materials have become one of the research hotspots in the field of tribology. Due to its diversity and controllability in terms of chemical composition, particle size and macroscopic morphology, its practical application and mechanism analysis in the field of tribology deserves in-depth exploration. In view of the above characteristics of this kind of material, layered double hydroxides (LDHs) are selected as the research object in this dissertation. They were regulated in many aspects such as size, morphology and chemical composition. Then, they were dispersed into different lubricating media to investigate the tribological properties.Firstly, based on the co-precipitation method, nano-LDHs with different micro-morphologies and chemical compositions were prepared by adjusting the experimental conditions and reactant materials in the reaction process. The synthesized sample was dispersed into the base grease by mechanical stirring. Under the same experimental conditions, by comparing the tribological properties of LDH additives with different micro-morphologies or chemical compositions, it was found that the addition of looser samples in the base grease can improve the friction and wear properties. In addition, the nickel-aluminum component shows a better lubricating effect.Subsequently, on the basis of the micro-emulsion method, LDH nanoplatelets with different sizes but similar structure and morphology were prepared by controlling the hydrothermal reaction time. Three samples were uniformly dispersed in the base oil. Under normal working conditions, the tribological properties can be improved by dispersing a small amount of LDH nanoplatelets into the base oil. In the sliding process, the relatively large size of the sample, due to its good crystal structure, formed a lubricating tribo-film with good mechanical properties and a uniform texture, exhibiting the most excellent and stable tribological properties.Then, the surface-modified LDH nanoplatelets were dispersed into the water to obtain a stable translucent suspension. Tribological tests of water-based lubricating fluids were performed under high contact pressures. It was found that the nano-LDH as a water-based additive can significantly improve the properties of friction reduction and wear resistance. The scope of application was further elucidated by changing the mass fraction of additives in the suspension and the relative sliding speed during the friction process.Finally, on the basis of discovering the superlubricity phenomenon of polyether aqueous solution, the influence of the addition of ultra-thin LDH nanoplatelets was explored. During the running-in period, the addition of LDH allows the sliding solid surfaces to be flattened and polished more quickly, and does not significantly affect the fluid continuity in the contact area and the shearing action between the hydrated layers. Therefore, it not only shortens the running-in process, but also improves the carrying capacity.
