Electrochemical corrosion behavior of Ti–35Nb–7Zr–5Ta powder metallurgic alloys after Hot Isostatic Process in fluorinated artificial saliva

Abstract

The present study aimed to evaluate the effect of the Hot Isostatic Process (HIP) process on the microstructure, phase stability and corrosion resistance of Ti35Nb7Zr5Ta powder metallurgy alloys. The corrosion resistance of titanium alloys was tested by analyzing the open circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and ion release in physiological Fusayama solution. Polarization curves showed that the Ti–35Nb–7Zr–2Ta alloy presented good passivation behavior thanks to its low current densities (<10−8 A/cm2) and high polarization resistance. The interpretation of an equivalent electric circuit (EEC) demonstrated the formation of a very stable oxide film on the alloy, as indicated by good capacitive behavior, high impedance values (>106 Ω cm2) at low frequencies and phase angles close to −90° according to the EIS results with less ion release.