Studies On Preparation And Tribological Properties Of Carbon Based Thin Films On Curved Metal Surfaces

In recent years,carbon based films have become the focus of attention in industry and science due to their ex cellent properties such as superhard,ultra-high thermal conductivity and ultra-low friction,especially their tribological properties.In this paper,different types of carbon based films(graphite like films,fullerene like hydrogen containing carbon films and graphene like films)were prepared on curved metal surfaces by plasma enhanced chemical vapor deposition(PECVD)and ball milling.The tribological properties of the films in different environments were investigated,and the friction reducing mechan ism of carbon based films on curved metal surfaces was revealed.The main results are as follows:1.Graphite like and fullerene like films were deposited on the surface of steel balls and silicon wafers by plasma enhanced chemical vapor deposition(PECVD).It was found that graphene nanoscrolls were formed at the sliding interface of the friction pair composed of graphite like and fullerene like in dry N₂,resulting in a significant decrease of the friction coefficient(?0.005).2.Fullerene like hydrogenated carbon films were deposited on the surface of steel balls and silicon wafers by plasma enhanced chemical vapor deposition(PECVD).The friction mechanism of fullerene like hydrogenated carbon films in atmospheric environment was discussed from the perspectives of internal structure,sliding ligands and environmental molecules.Combined with the first principles calculation,the ultra-low friction behavior of fullerene like carbon films can be attributed to the low interface electron density of sliding pair,the low oxidation degree of environmental molecules and the friction induced in-situ formation of graphite nanoparticles.3.Large area and continuous graphene thin films were prepared on the surface of highly curved steel balls by ball milling method through collision and random rolling between steel balls and graphene powder,and by virtue of the interlayer slip ability of graphene sheets.The amorphous structure introduced by the collision between steel balls during ball milling makes graphene had a three-dimensional carbon network containing graphene structure,which leads to its strong binding force with steel balls.The results show that the average friction coefficient decreases from 0.043 to 0.022,and the depth and width of wear scar decrease significantly,which enriches the preparation methods of graphene films.