Abstract In this work, we designed three series of tribo-couples based on amorphous carbon films including GLC, DLC and PLC that were modified by graphene quantum dots (GQDs). The tribo-testing environment was controlled at harsh conditions (like heavy load and high speed) in dry nitrogen atmosphere using bare and film-coated bearing steel balls as counterbodies, respectively. Through the tribochemical interactions, the self-mated DLC system obtained a surperlubricity state (μ = 0.01). During the whole sliding, the contact surface of the upper counterfacing ball was covered by 2D-layered carbon and graphitic lubricants induced via structural transformation of GQDs. Meanwhile, the tribofilm of the disc wear track was composed of a silica-like SiOx boundary layer and a multicomponent mixed-layer induced by tribochemistry. Compared to the self-mated DLC system, the structural boundary enriched with SiOx compounds was not formed at the bottom region of the tribofilm for the bare steel system; meanwhile, the disc wear track was covered by a thicker tribofilm containing plenty of degraded GQDs. This inferred the fact that the formation of a nanostructured sliding interface was the key to realize superlubricity. These discoveries successfully afforded a lubrication mechanism of GQDs for solid lubricant in applications of engineering and industry.

中文翻译：

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高接触压力下石墨烯量子点改性DLC薄膜超润滑性的摩擦化学机制

摘要 在这项工作中，我们设计了基于石墨烯量子点（GQDs）改性的 GLC、DLC 和 PLC 三个系列的基于非晶碳薄膜的摩擦偶。摩擦测试环境分别使用裸轴承钢球和薄膜涂层轴承钢球作为配对体，在干燥氮气环境中的恶劣条件（如重载和高速）下进行控制。通过摩擦化学相互作用，自配合 DLC 系统获得了超润滑状态（μ = 0.01）。在整个滑动过程中，上对向球的接触面被二维层状碳和石墨润滑剂覆盖，这些润滑剂是通过 GQD 的结构转变引起的。同时，盘磨损轨道的摩擦膜由二氧化硅状SiOx边界层和摩擦化学诱导的多组分混合层组成。与自配对 DLC 系统相比，裸钢系统的摩擦膜底部区域没有形成富含 SiOx 化合物的结构边界；同时，圆盘磨损轨迹被更厚的摩擦膜覆盖，其中包含大量降解的 GQD。这推断出纳米结构滑动界面的形成是实现超润滑性的关键。这些发现成功地为工程和工业应用中的固体润滑剂提供了 GQD 的润滑机制。这推断出纳米结构滑动界面的形成是实现超润滑性的关键。这些发现成功地为工程和工业应用中的固体润滑剂提供了 GQD 的润滑机制。这推断出纳米结构滑动界面的形成是实现超润滑性的关键。这些发现成功地为工程和工业应用中的固体润滑剂提供了 GQD 的润滑机制。