Comparison of the Phase Composition and Nanohardness of Gradient TiN/TiO2 Coatings on Ti5Al4V Alloy Deposited by Different PVD Methods

Abstract

The effect of the deposition technology of gradient TiN/TiO2 coatings, applied on Ti5Al4V substrate, on the phase composition and mechanical properties has been studied. The films have been applied by reactive magnetron sputtering and cathodic arc and glow-discharge techniques. The coatings' properties have been studied by X-ray diffraction (XRD) and nanoindentation tests. The results in the present study show that the application of both methods are capable to form polycrystalline TiN and TiO2. The coatings deposited by magnetron sputtering are monophasic and polycrystalline as TiO2 is in the form of anatase. Those, applied by cathodic arc and glow-discharge technique, TiO2 layer is in the form of double-phase structure of rutile and anatase. The measured hardness is similar for the coatings deposited via both methods. The hardness of magnetron sputtered coatings is 6.3±1.1 GPa. The values for coatings obtained by glow-discharge is 6.1±1.4 GPa.