Protective effect of plasma-assisted PVD deposited coatings on Ti-6Al-4V alloy in NaCl solutions

Author(s)

Oliveira, V. M. C. A. ; Vazquez, A. M. ; Aguiar, C. ; Robin, A. ; Barboza, M. J. R.

• Document type: Journal article
• Source: MATERIALS & DESIGN; v. 88, p. 8-pg., 2015-12-25.

Abstract

Ti-6Al-4V is a (alpha + beta) two-phase alloy with high corrosion resistance in oxidizing acids and neutral media. However, this alloy does not show corrosion resistance in reducing acids and complexing media. Furthermore, the resistance decreases with increasing temperature. Hard nitride based coatings are almost chemically inert and therefore widely used in many applications that require high corrosion resistance. This study aimed to improve the corrosion resistance of Ti-6Al-4V alloy by plasma-assisted PVD deposited TIN and TiAlN/TiAlCrN coatings. The corrosion behavior of uncoated and coated Ti-6Al-4V alloy was evaluated in 3.5 wt.% NaCl solution at 25, 60 and 80 degrees C, using open-circuit potential versus time measurements, potentiodynamic polarization and electrochemical impedance spectroscopy. The uncoated and coated alloy showed a passive behavior under all conditions. TIN and TiAlN/TiAlCrN coated alloy showed a superior corrosion resistance evidenced by lower corrosion current densities and higher impedance values compared to the uncoated sample. Increasing temperature decreased the corrosion resistance of the uncoated and coated Ti-6Al-4V alloy. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 13/00885-2 - Evaluation of TiN PVD coating on creep resistance of Ti-6Al-4V
• Grantee: Carla de Aguiar
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 11/00511-0 - Study of the phenomena of creep, corrosion and isothermal oxidation of Ti-6Al-4V subjected to TiN and TiAlN coatings deposited by plasma-assisted PVD technologies.
• Grantee: Verônica Mara de Oliveira Velloso
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/00886-9 - Study on the creep phenomenon of Ti-6Al-4V submitted to TiAl coating deposited by PVD plasma-assisted technique
• Grantee: Amira Muci Vazquez
• Support Opportunities: Scholarships in Brazil - Scientific Initiation