Rolling-Sliding Mechanism in Achieving Solid Superlubricity of Amorphous Carbon Films

Solid superlubricity describes the state that coefficient of friction is lower than 10^-3 between two sliding interfaces. The development of solid superlubricity mechanism and superlubricity technology are of great significance. Diamond-like carbon films (DLC) superlubricity is heavily relied on the passivation of the introduced heteroatoms (hydrogen), especially when the content of hydrogen is higher than 40%. However, carbon films with high hydrogen content are just a fraction according to ternary phase diagram of DLC films. A large number of passivated or less passivated carbon films are lack of theoretical guidance in achieving superlubricity. Under the basic of latest progress at home and abroad, this review proposed the rolling-sliding mechanism towards disordered and unpassivated or less passivated carbon films, which includes sliding mechanism, rolling mechanism and rolling-sliding mechanism. Furthermore, the possible development tendency and design principles and programs of solid superlubricity were discussed.