Sha Tian-Dong, Pang Hua, Fang Liang, Liu Hui-Xian, Chen Xin-Chun, Liu Da-Meng, Luo Jian-Bin
State Key Laboratory of Tribology, Tsinghua University, Beijing, 100084, People's Republic of China.
Nanotechnology. 2020 May 15;31(20):205703. doi: 10.1088/1361-6528/ab70cd. Epub 2020 Jan 28.
Superlubricity between a cone-shaped (sharp) silicon tip and graphite remains a challenge in the nanotribology field. In this paper, an efficient method of achieving superlubricity between a cone-shaped silicon tip and graphite was proposed. Graphite nanoflakes were transferred onto the silicon tip by repeatedly rubbing against the scratches produced by nanolithography on a graphite surface. The superlubricity between the graphite nanoflakes-wrapped tip and highly oriented pyrolytic graphite (HOPG) was attained, and the friction coefficient was reduced to 0.0007. At low normal loads, the frictional force was small and showed a strong correlation with the sliding angle, but as the normal load increased, this dependence gradually decreased. It was firstly found that the transferred graphite nanoflakes on the contact zone of the silicon tip could be transformed into amorphous carbon layers induced by the shear force and high pressure during the superlubricity test process.
在纳米摩擦学领域，锥形（尖锐）硅 tip 与石墨之间的超润滑性仍然是一个挑战。本文提出了一种在锥形硅 tip 与石墨之间实现超润滑性的有效方法。通过反复摩擦石墨表面上纳米光刻产生的划痕，将石墨纳米薄片转移到硅 tip 上。实现了石墨纳米薄片包裹的 tip 与高度取向热解石墨（HOPG）之间的超润滑性，摩擦系数降至 0.0007。在低法向载荷下，摩擦力较小且与滑动角度有很强的相关性，但随着法向载荷增加，这种依赖性逐渐降低。首次发现，在超润滑性测试过程中，硅 tip 接触区域上转移的石墨纳米薄片可在剪切力和高压作用下转变为非晶碳层。
