Tribological behavior and mechanism on metal/graphite end-face contact pair with low temperature liquid nitrogen

A low-temperature Liquid Nitrogen Ring-on-Ring end-face contact friction Test Platform (LNR-RTP) was set up and applied to test the tribological behavior on metal/graphite ring-on-ring end-face contact pair. The friction coefficients and wear rates were obtained, and the wear mechanism was analyzed. The results show the friction coefficient increases with the rotational speed under the low temperature conditions and the low load from 50 to 100 N. With the load increasing, the friction coefficient is stable with the change of rotational speed, which is 0.05. The wear cross-section shows a taper shape from the inner to outer diameter, which implies a transition of the wear mechanism from the adhere wear to three-body wear under the low temperature conditions.