[论文解读] Solid-Lubrication Performance of Ti3C2Tx -- Effect of Tribo-Chemistry and Exfoliation

Andreas Rosenkranz, Bo Wang+8 more|arXiv (Cornell University)|Jun 5, 2023

MXene and MAX Phase Materials参考文献 44被引用 13

一句话总结

本论文研究了摩擦化学过程和 MXene 解层对 Ti3C2Tx-Coatings 固体润滑性能的影响，并在不同载荷和频率下比较薄多层与解层少层 MXene 的表现。

ABSTRACT

Multi-layer Ti3C2Tx coatings have demonstrated an outstanding wear performance with excellent durability due to beneficial tribo-layers formed. However, the involved formation processes dependent on the tribological conditions and coating thickness are yet to be fully explored. Therefore, we spray-coated Ti3C2Tx multi-layer particles onto stainless steel substrates to create coatings with two different thicknesses and tested their solid lubrication performance with different normal loads (100 and 200 mN) and sliding frequencies (1 and 2.4 Hz) using linear-reciprocating ball-on-disk tribometry. We demonstrate that MXenes' tribological performance depends on their initial state (delaminated few-layer vs. multi-layer particles), coating thickness, applied load and sliding frequency. Specifically, the best behavior is observed for thinner multi-layer coatings tested at the lower frequency. In contrast, coatings made of delaminated few-layer MXene are not as effective as their multi-layer counterparts. Our high-resolution interface characterization by transmission electron microscopy revealed unambiguous differences regarding the uniformity and chemistry of the formed tribo-layers as well as the degree of tribo-induced MXenes' exfoliation. Atomistic insights into the exfoliation process and molecular dynamic simulations quantitatively backed up our experimental results regarding coating thickness and velocity dependency. This ultimately demonstrates that MXenes' tribological performance is governed by the underlying tribo-chemistry and their exfoliation ability during rubbing.

研究动机与目标

• 了解初始 MXene 状态（解层少层 vs 多层）如何影响摩擦学性能。
• 在不同载荷和滑动频率下，考察涂层厚度对磨耗和润滑的作用。
• 阐明涂层-对表界面的摩擦化学过程与解层动力学。

提出的方法

• 将 Ti3C2Tx 多层颗粒喷涂到不锈钢上以制备两种厚度的涂层。
• 在 100 和 200 mN 载荷，以及 1 和 2.4 Hz 频率下进行线性往返球盘摩擦测试。
• 使用高分辨率透射电子显微镜（TEM）对界面的摩擦层进行表征。
• 利用原子级见解与分子动力学模拟来理解解层及其对性能的影响。
• 将实验结果与模拟结果相关联，以将性能归因于摩擦化学作用与解层能力。

实验结果

研究问题

• RQ1 初始 MXene 状态（解层少层 vs 多层）如何影响固体润滑性能？
• RQ2 在不同载荷和滑动频率下，涂层厚度对摩擦学结果的影响是什么？
• RQ3 界面上会发生哪些摩擦化学过程，解层在摩擦过程中的作用如何影响性能？
• RQ4 原子级模拟能否再现观测到的厚度和速度依赖的解层及摩擦层形成？

主要发现

• 在较低频率下，较薄的多层涂层表现出最好的润滑行为。
• 在所测试条件下，解层少层 MXene 涂层不如多层对等的涂层有效。
• 高分辨率 TEM 显示摩擦层的均匀性和化学成分因初始 MXene 状态和摩擦条件而异。
• 在滑动过程中解层有助于摩擦层的形成，并且受涂层厚度和滑动速度控制。
• 分子动力学与原子级见解在厚度、速度与解层方面定量支持了实验趋势。
• 总体而言，MXene 的摩擦学性能受摩擦化学作用及其在摩擦中的解层能力控制。