Durability and degradation mechanism of graphene coatings deposited on Cu substrates under dry contact sliding

The durability and degradation mechanism of graphene coatings deposited on Cu substrates under dry contact sliding were assessed. The motivation was to develop an ultra-thin protective coating for precision components based on the excellent mechanical properties of graphene. The graphene coatings were deposited on polycrystalline Cu substrates by chemical vapor deposition at atmospheric pressure. The uniformity and quality of the coating could be improved by increasing the growth time from 5 to 20 min. This also led to increase in the durability of the coating which was determined by noting the point of drastic increase in friction. Eventual degradation of the graphene coating with increasing number of sliding cycles could be characterized by the transformation of graphene to amorphous carbon. Nevertheless, the ability of ultra-thin graphene coating in protecting the surface of metal under dry contact sliding was clearly demonstrated at the macro-scale.