Preparation of a gradient Ti–TiOC-carbon film by electro-deposition

Carbon films with a Ti–O–C graded interlayer were deposited on titanium by electrochemical reduction of carbonate ions in a molten LiCl–KCl–K2CO3 system. A graded interlayer, prepared by the joint process of oxidation in air and electrochemical reactions on titanium substrate in the LiCl–KCl melt, can enhance obviously adhesion between the titanium substrate and carbon films. The formation of carbon films with a Ti–O–C gradient was demonstrated by SEM and XRD, and the adhesion strength of the carbon films was measured by scratch test.

► A Ti–O–C gradient was prepared on site.
► Carbon film was deposited on titanium in molten salt.
► The Ti–O–C gradient improved adhesion of carbon film to titanium substrate.
► The method to produce the Ti-O-C gradient could be extended to other metal substrates.