Characterization of tantalum and tantalum nitride films on Ti6Al4V substrate prepared by filtered cathodic vacuum arc deposition for biomedical applications

• Published in: Surface & coatings technology Vol. 365; pp. 24 - 32
• Main Authors: Hee, Ay Ching, Zhao, Yue, Jamali, Sina S., Bendavid, Avi, Martin, Philip J., Guo, Hongbo
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.05.2019; Elsevier BV
• Subjects: Arc deposition; Argon; Bacterial corrosion; Biocompatibility; Biomedical materials; Corrosion resistance; Electrochemical impedance spectroscopy; Localized corrosion; Nitrogen; Photoelectrons; Protective coatings; Spectrum analysis; Substrates; Surface treatment; Surgical implants; Tantalum compounds; Tantalum films; Tantalum nitrides; Tantalum oxides; Thickness; Thin films; Titanium alloys; Titanium base alloys; X-ray photoelectron spectroscopy; Tantalum films; Tantalum nitrides; X-ray photoelectron spectroscopy; Electrochemical impedance spectroscopy
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2018.05.007

This paper explores tantalum and tantalum nitride thin films produced by filtered cathodic vacuum arc deposition method as bio-stable surface treatment for Ti6Al4V titanium alloy. Effect of nitrogen to argon gas ratio on microstructure of the deposited film has been investigated. Corrosion behaviour of the films in simulated biological fluid solution was evaluated by electrochemical impedance spectroscopy. It was found that both the Ta and TaN films enhanced corrosion resistance of the Ti6Al4V substrate with the best protective characteristics achieved by the TaN film deposited at 0.25 N2/Ar gas ratio. The protective characteristic was attributed to the formation of tantalum oxide and oxynitride compound at the surface, as verified by X-ray photoelectron spectroscopy. Increasing N2/Ar gas ratio increased susceptibility to localized corrosion. The corrosion resistance decreased as the thickness of the film increased to 1 μm. •Incorporation of nitrogen improves the corrosion resistance of Ta coated Ti6Al4V.•XPS results confirm the formation of a TaON after corrosion of the TaN film surface.•The improved corrosion resistance was attributed mainly to the formation of TaON.