Determination of structural, mechanical and corrosion properties of Nb₂O₅ and (Nb_yCu_1−y)O_x thin films deposited on Ti6Al4V alloy substrates for dental implant applications

In this paper comparative studies on the structural, mechanical and corrosion properties of Nb₂O₅/Ti and (Nb_yCu_1−y)O_x/Ti alloy systems have been investigated. Pure layers of niobia and niobia with a copper addition were deposited on a Ti6Al4V titanium alloy surface using the magnetron sputtering method. The physicochemical properties of the prepared thin films were examined with the aid of XRD, XPS SEM and AFM measurements. The mechanical properties (i.e., nanohardness, Young's modulus and abrasion resistance) were performed using nanoindentation and a steel wool test. The corrosion properties of the coatings were determined by analysis of the voltammetric curves. The deposited coatings were crack free, exhibited good adherence to the substrate, no discontinuity of the thin film was observed and the surface morphology was homogeneous. The hardness of pure niobium pentoxide was ca. 8.64 GPa. The obtained results showed that the addition of copper into pure niobia resulted in the preparation of a layer with a lower hardness of ca. 7.79 GPa (for niobia with 17 at.% Cu) and 7.75 GPa (for niobia with 25 at.% Cu). The corrosion properties of the tested thin films deposited on the surface of titanium alloy depended on the composition of the thin layer. The addition of copper (i.e. a noble metal) to Nb₂O₅ film increased the corrosion resistance followed by a significant decrease in the value of corrosion currents and, in case of the highest Cu content, the shift of corrosion potential towards the noble direction. The best corrosion properties were obtained from a sample of Ti6Al4V coated with (Nb_0.75Cu_0.25)O_x thin film. It seems that the tested materials could be used in the future as protection coatings for Ti alloys in biomedical applications such as implants. - Highlights: • Nb₂O₅ and Nb₂O₅:Cu thin films were deposited on a Ti–Al–V surface using the magnetron sputtering. • Nb₂O₅ and Nb₂O₅:Cu thin films improve the surface mechanical properties of Ti6Al4V alloy. • All prepared thin films improved the corrosion properties of Ti–Al–V alloy. • The thin films obtained could be used as a barrier layer for Ti–Al–V surface. • Obtained thin films can prevent against allergies and metalosis, caused by Ti implants