Electrochemical corrosion behavior of biomedical Ti–22Nb and Ti–22Nb–6Zr alloys in saline medium

Abstract

The aims of this study were to investigate the effects of Zr addition and potentiodynamic polarization on the microstructure and corrosion resistance of Ti-22Nb and Ti-22Nb-6Zr alloy samples. The corrosion tests were carried out in 0.9% NaCl at 37 8C and neutral pH value, utilizing the OCP, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The results of XRD and optical microscopy indicated that the addition of Zr stabilized the b phase, which plays a crucial role in the corrosion resistance improvement of the Ti-22Nb-6Zr alloy. From the polarization curves, it can be seen that the alloys exhibited a wide passive region without the breakdown of the passive films and also low corrosion current densities. In addition, the values of the corrosion current densities and passive current densities decreased with the addition of 6 at% Zr into the Ti-22Nb alloy. The EIS results of these two alloy samples after 1-h immersion in 0.9% NaCl solution, and being fitted by R S (Q P R P ) model, suggested that the corrosion resistance of the passive films improved with the addition of Zr and only a single passive film formed on the surfaces. However, two time constants were observed for the Ti-22Nb and Ti-22Nb-6Zr alloy samples after potentiodynamic polarization, the spectra of which can be fitted using the R s (Q o (R o (Q b R b ))) model. In addition, the corrosion resistance of the two alloy samples was reinforced significantly because of polarization when compared to the immersed samples. All these observations suggested a nobler electrochemical behavior of the titanium alloys with the addition of Zr element and after polarization.

Surface Characterization and Cell Response of Binary Ti-Ag Alloys with CP Ti as Material Control

“…This model has been widely discussed for the single passive layer formed on the surface of titanium alloys [14,15] .…”

Influence of fluoride on the electrochemical behvior of a new synthesized Ti-10Ta-2Mo alloy for biomedical applications

“…Electrochemical impedance spectroscopy measurements were performed using the electrochemical interface Solartron 1287 combined with the frequency response analyser Solartron 1260 [7], controlled by the Ecorr/Zplot Software. The frequency was scanned from 100 KHz down to 10 mHz and a 10 mV sinusoidal potential peak to peak was applied.…”

“…Their highly chemical stability is due to formation of a very resistant and protective oxide layer on their surface [1][2][3]. The phenomenon of passivation is a 0.9%NaCl [4][5][6][7], Ringer's solution [8][9][10], Hank's solution [11,12], Phosphate buffered saline solution PBS [13,14] and other simulated physiological media.…”

“…Although this alloy is still widely utilized in medicine, some concern has been recently expressed over its use since it appears that small amounts of both vanadium and aluminum, released in the human body, induce possible cytotoxic effect and neurological disorders, respectively [27,28]. Due to the detrimental effect of Aluminum and vanadium, different titanium alloys containing non toxic elements (Nb, Ta, Mo, Zr) known as β-stabilizer elements, were developed in order to replace Ti-6Al-4V, such as Ti-Ta [29,30], Ta-Mo [7,8,31,32]; few works are available in the literature about the mechanical and corrosion behavior of Ti-Ta-Mo ternary alloy [33,34].…”

Corrosion of Shape Memory and Superelastic Alloys

“…Wang et al studied the corrosion resistance of Ti-22Nb and Ti-22Nb-6Zr alloys [137]. The corrosion behavior was evaluated in 0.9% NaCl at 37 C and neutral pH using OCP, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques [137].…”