Electrochemical Deposition Of Carbon Films On Tantalum In Molten Salt

Carbon films have been widely used in various fields for its useful chemical and physical properties. Compared with the methods of physical vapor deposition and chemical vapor deposition, electrochemical deposition has many advantages such as simple experimental equipment, abundant and cheap materials, low temperature and the fast deposition speed. So it can produce carbon films in a simpler and more economical way.In this study, carbon films have been prepared on tantalum substrate by electrochemical reduction of the carbonate in KCl-LiCl eutectic molten salt. The carbide gradient was also prepared by high temperature oxidation of the substrate combined with the electrochemical deposition, which can enhance adhesion strength of carbon films to the tantalum substrate; The operating conditions, which affected the deposition of the carbon films, were discussed with the aim of preparing the uniform and continuous carbon films, such as oxidation conditions, working temperature and the amount of deposited carbon. The main results were summarized as follows:Carbon films with carbide gradient were prepared by a joint method of oxidation of the substrate, electro-deoxidation of the oxide films and successively electro-deposition of carbon on tantalum substrate; The gradient between the carbon films and tantalum substrate achieved successive evolution of composition and structure from substrates to carbon films, which can enhance the adhesion strength of carbon films to the substrates; A gradient of tantalum and tungsten carbide can be prepared more easily on tantalum substrate with the increasing of the working temperature, the amount of deposited carbon and graphitization degree also increased; The carbon films obtained were constituted of micron-sized and quasi-spherical carbon particles, which were stacked layer by layer on substrate during the deposition. Furthermore, the size of carbon particles increased with the amount of deposited carbon on the substrate; The amount of deposited carbon was increased with the electro-deposition time and electro-deposition voltage that increased the thickness of the carbon films, and then led to the delamination of carbon films from the substrate; The macro-and-micro roughness of the surface of the substrate was increased by oxidation and electro-deoxidation of tantalum substrate which were favorable for the nucleation of carbon particles on tantalum substrate; The adhesion strength of oxide films affected the quality of carbon films, the decline of its adhesion strength can led to the delamination of carbon films.