Graphite Films Deposited on Metal Surface by Pulsed Electrical Discharge Machining

Abstract

The paper presents the results of experimental research on the physics of natural graphite film formation, the establishment of chemical composition and functional properties of the graphite films, formed on metal surfaces, as a result of the action of plasma in the air environment, at a normal pressure, under the pulsed electrical discharge (PED) conditions. The continuity of the formed film, the thickness of the layer, the diffusion depth, the micro-hardness of the surface layer, the potential of corrosion, and the wear resistance are investigated. It is shown that the use of electrode tool made of pyrolytic graphite improves the mechanical properties at the microscopic level, such as tensile strength. The behaviour of films in an exceptional manner with reference to solubility in different environments is highlighted and the hypothesis that they could contain space structures such as fullerenes and carbon nanotubes are emphasized. Testing studies, using three processing regimes, have proved that the maximum breaking force of samples made from graphite-coated steel-3 increases essentially as compared to the untreated sample. It is demonstrated that the graphite films made by PED method have similar characteristics to those of fullerene or carbon nanotubes.