Superlubricity of the DLC films-related friction system at elevated temperature

Superlubricity is defined as a sliding regime in which friction or resistance to sliding almost vanishes. While there are a number of superlubricity, providing a high temperature superlubricity remains a challenge. Here we present a high temperature superlubricity achieved from the diamond like carbon (DLC) films friction system. Superlubricity is found about 0.008 for more than 100 000 seconds at the steady state at the temperature of 600 degrees C due to the formation of the self-generated lubricious composite oxides of gamma-Fe2O3 and SiO2 at the contact surfaces through tribochemistry reaction during the running-in process. We propose a superlubricity system based on the repulsive electrostatic forces between the self-generated composite oxides due to high temperature oxidation reaction and the shielding action of hydrogen at the contact surface, which is seem to be a reasonable explanation for super low friction at the elevated temperature.