We investigate the dependence of friction forces on normal load in incommensurate micrometer size contacts between atomically smooth single-crystal graphite surfaces under ambient conditions. Our experimental results show that these contacts exhibit superlubricity (super-low friction), which is robust against the application of normal load. The measured friction coefficients are essentially zero and independent of the external normal load up to a pressure of 1.67 MPa. The observation of load-independent superlubricity in micro-scale contacts is a promising result for numerous practical applications.
@article{arxiv.1602.02557,
title = {Observation of normal-force-independent superlubricity in mesoscopic graphite contacts},
author = {Cuong Cao Vu and Shoumo Zhang and Michael Urbakh and Qunyang Li and Q. -C. He and Quanshui Zheng},
journal= {arXiv preprint arXiv:1602.02557},
year = {2016}
}