Corrosion behaviour and microstructure of tantalum film on Ti6Al4V substrate by filtered cathodic vacuum arc deposition

Publication date: 31 August 2017
Source:Thin Solid Films, Volume 636
Author(s): Ay Ching Hee, Yue Zhao, Sina S. Jamali, Philip J. Martin, Avi Bendavid, Hui Peng, Xiawei Cheng
Tantalum (Ta) films of about 100nm in thickness were fabricated onto Ti6Al4V substrate using a filtered cathodic vacuum arc deposition system with and without a −100V bias between the substrate and the chamber wall. The structure of the deposited film at zero substrate bias exhibits pure tetragonal phase (beta-Ta), and body-centred cubic structure (alpha-Ta) is found as the substrate bias increased to −100V. The film deposited at −100V bias shows a significant improvement in cohesion as compared to the film deposited without substrate bias. Potentiodynamic polarization and electrochemical impedance tests in phosphate buffered saline solution revealed that the Ta film at −100V bias shows good corrosion resistance with a low corrosion current density of 0.009μA·cm⁻². The film shows hydrophobic characteristics, low surface free energy and an inert surface presenting a uniform oxide layer, which is promising for potential biomedical implant applications.