Deposition of Ti/C compositional gradient film onto superplastic Ti‐alloy by magnetron sputtering

Abstract

AbstractDeposition of Ti/C compositional gradient film onto superplastic titanium‐based alloy such as Ti6Al4V or Ti4.5Al3V2Fe2Mo was performed by magnetron sputtering, in order to improve not only the biocompatibility and the abrasion resistance of the alloy but also the adhesion between the deposited film and the alloy substrate while preserving the high hardness of such ceramic coatings. The Ti/C compositional gradient films were deposited by co‐sputtering of two sputter cathodes which had pure titanium and titanium carbide targets, respectively, and their compositional gradient was realized by varying continuously the electric power supplied to each sputter cathode. Under visual observation, the obtained film appeared to be uniform and adhesive. According to AES in‐depth profiles, the carbon (C) concentration in the film gradually decreased in depth direction from the surface toward the substrate, confirming that Ti/C compositional gradient film had formed on the alloy substrate. On the basis of XRD, it was found that titanium carbide (TiC) and α‐titanium phases were formed in the films. Furthermore, the Vickers hardness of the films reached over HV = 1800. Therefore not only the biocompatibility and the abrasion resistance of the alloy but also the adhesion of the deposited hard coatings were expected to be improved by this method. Copyright © 2004 John Wiley & Sons, Ltd.