Comparison of structural, mechanical and corrosion properties of (Ti0.68W0.32)Ox and (Ti0.41W0.59)Ox thin films, deposited on TiAlV surface by electron beam evaporation

Abstract

In this paper, comparative studies of the structural, mechanical and corrosion properties of TiO2-WO3 thin films, with different contents of WO3, have been investigated. The thin films were formed using the electron beam evaporation method, on the Ti6Al4V surface. After the deposition process both thin films were additionally annealed at 1073 K in a computer-controlled Nabertherm tubular furnace in an ambient atmosphere. The structural characteristics of the thin films obtained, before and after the annealing process, were examined using SEM and XRD measurements. The mechanical properties of the coatings were determined by nanoindentation measurements. The corrosion properties of the thin films were determined by an analysis of the voltammetric curves. The results obtained show that the layer with the higher content of tungsten – (Ti0.41W0.59)Ox annealed at 1073 K is characterised by the best mechanical and corrosion properties from all tested samples. The hardness obtained for this sample was equal to 14.9 GPa, and was about four times higher than the value obtained for the same sample before the annealing process, and almost one and half times higher than the value obtained for the annealed sample with a lower content of tungsten. In addition, the value of corrosion current density for this sample was equal to 6.02 ∙ 10− 9 A/cm2 and was lower than the value obtained for the same sample before the annealing process. This indicates that after the annealing process the mechanical and corrosion properties of the (Ti0.41W0.59)Ox thin film improved, as compared with the layer with the lower content of tungsten, for which the corrosion properties after the annealing process degraded.