Corrosion behavior of new quaternary ZrNbTiAl alloys in simulated physiological solution using electrochemical techniques and surface analysis methods

[Display omitted] •Metastable beta ZrTiNbAl alloys with homogeneous composition distributions in the matrix were synthesized.•Corrosion resistance of ZrTiNbAl alloys in Ringer’s solution at 37°C was due to the formation of passivating oxide films on their surface.•Localized breakdown occurred for low Ti contents in the alloy above a certain anodic polarization.•Surface films formed on alloys of Zr/Ti ratio less than one were stable at positive polarizations. The potential biomedical application of three new quaternary Zr alloys, namely Zr6Ti15Nb4Al, Zr32Ti15Nb4Al, and Zr49Ti15Nb4Al, was evaluated in vitro using electrochemical methods complemented with surface analysis of corrosion resistance. Cyclic potentiodynamic polarization (CCP) and electrochemical impedance spectroscopy (EIS) tests were performed in Ringer’s solution at 37°C. The electrochemical behavior of the ZrTiNbAl quaternary alloys was consistent with the formation of passivating oxide films on the surfaces of these materials. Localized breakdown of the oxide layer occurred on Zr6Ti15Nb4Al and Zr32Ti15Nb4Al alloys subjected to positive anodic polarization, a feature confirmed by scanning electron microscopy (SEM) on retrieved samples. The Zr49Ti15Nb4Al alloy, which had the highest titanium (49wt.%) content, exhibited a larger passive range in the polarization curve and was immune to localized corrosion breakdown in a simulated physiological solution for the range of polarizations that can occur in the human body.