Carbon dots as an additive for improving performance in water-based lubricants for amorphous carbon (a-C) coatings

As a new type of carbon material, carbon dots (CDs) with exceptional properties are regarded as a type of potential water-based lubricant additive. In this study, it is first demonstrated that CDs perform excellently when used as lubricant additives for water-lubricated amorphous carbon (a-C) contacts. The results show that the introduction of CDs into water at a concentration of 0.1 wt% could reduce friction and wear in a-C contacts by 33% and 80%, respectively. Additionally, the lubricating performance of CDs is highly sensitive to its adding concentration. The excellent tribological performance of CDs results from the minimized CDs sediment particles (deposited in situ on worn a-C surfaces) and the reduced friction and wear via nano-bearing and nano-filling mechanisms. With high CDs concentrations, however, micron and submicron-sized sediment particles form when friction occurs and cause undesirable abrasive wear. For water-lubricated a-C contacts, therefore, the CDs concentration is the crucial determinant of lubrication performance that has to be appropriately controlled. (C) 2019 Elsevier Ltd. All rights reserved.

作为一种新型碳材料，具有优异性能的碳点（CDs）被视为一种潜在的水基润滑剂添加剂。在本研究中，首次证明了碳点用作水润滑非晶碳（a - C）接触的润滑剂添加剂时性能卓越。结果表明，将浓度为0.1 wt%的碳点引入水中，可使a - C接触的摩擦和磨损分别降低33%和80%。此外，碳点的润滑性能对其添加浓度高度敏感。碳点优异的摩擦学性能源于最小化的碳点沉积颗粒（原位沉积在磨损的a - C表面）以及通过纳米轴承和纳米填充机制降低的摩擦和磨损。然而，在高碳点浓度下，摩擦发生时会形成微米和亚微米尺寸的沉积颗粒，从而导致不良的磨粒磨损。因此，对于水润滑的a - C接触，碳点浓度是润滑性能的关键决定因素，必须适当控制。（C）2019爱思唯尔有限公司。保留所有权利。