Superlubricity of carbon nitride coatings in inert gas environments

Abstract Tribological system with carbon nitride (CNx) coatings is promising to provide superlow friction in an inert gas environment without any specific lubricants. Such stable and superlow friction is key to both formation of an invisible transferred carbon layer of the thickness of several nanometers (so called as tribolayer) and termination of hydrogen and hydroxyl groups dissociated from water molecule in the inert gas environment to the tribolayer.