Research on superlubric carbonic materials

实现理想的零能耗无摩擦机械系统是摩擦学研究的终极目标之一。自理想无摩擦滑动概念提出以来，迄今为止对超低摩擦机理的基础研究主要基于两种不同的机理：不适应接触和弱界面相互作用。然而，很少有针对润滑工程实际应用的研究。最近我们已经证明了一个C_<60>的单层体系在石墨壁的约束下表现出超低的动态摩擦。本课题拟开展三个主要研究课题：(1)超润滑碳材料的精细结构研究(2)可测量皮牛顿摩擦力的摩擦力显微镜的研制。(3)发现新型超润滑剂体系。它能够通过化学和热处理将C_<60>分子插入石墨膜中。C_<60>插层石墨膜由C_<60>单层和石墨层（石墨烯）交替紧密堆积而成。当载荷增加到100nN时，摩擦力图呈现出明显的周期性规律。有趣的是，这种周期性反映了他的C_<60>的密包结构，这表明C_<60>的迁移率是由石墨壁的挤压和/或C_<60>分子之间的化学键形成的冻结。预计这些薄膜的摩擦机制与它们的运动辅助下的多级滑动有关。静止零摩擦发生在2.3mmx2.3nm的相当大的面积上，并且在任何滑动方向上都不出现摩擦，这对于实现纳米和微机械以及新兴的突出产业是非常重要的发现。

It is one of the ultimate goals of tribology researchers to realize an ideal friction-free machinery system with zero energy consumption. Since the proposal of the concept of an ideal frictionless sliding, fundamental studies on ultralow friction mechanism have been carried out to date based on mainly two different mechanisms, incommensurate contact and weak interfacial interaction. However there have been few studies aim of which is for practical use in lubrication engineering. Recently we have shown that a C_<60> monolayer system confined by graphite walls exhibits ultralow dynamic friction. In this project, three main subjects have been planned : (1) Research on fine structures of superlubric carbonic materials(2) Development of frictional force microscopy which can measure a friction force of piconewton. (3)Discovery of novel superlubric system. It was able to intercalate C_<60> molecules into graphite films using chemical and thermal treatments. The C_<60>intercalated graphite films consist of alternating close-packed C_<60> monolayers and graphite layers(graphenes). When the loading increases up to 100nN, friction force map provides clear periodic pattern. Interestingly, this periodicity reflects a C_<60> close-pack structure of him, which indicates that the mobility of C_<60>is frozon by the squeeze of graphite walls and/or by the creation of a chemical bonding between C_<60> molecules. The friction mechanism of these films is expected to relate to exhibit a multistage sliding assisted by their movements. Stationary zero friction occurs at a quite large area of 2.3mmx2.3nm in size, and no friction appears for any sliding direction, which is a tremendously important discovery for the realization of nano-and micromachines and for a new and prominent industry.