The Effect of Annealing Temperature and Immersion Time on the Active–Passive Dissolution of Biomedical Ti70Zr20Nb7.5Ta2.5 Alloy in Ringer’s Solution

Abstract

Because of their superior biocompatibility, chemical stability, and mechanical strength, Ti and Ti-based alloys are commonly utilized in orthopedic dentistry. In Ringer’s solution (RS), the corrosion behavior of the Ti70Zr20Nb7.5Ta2.5 alloy was examined as an alternative potential material for Ti and Ti6Al4V ( T6A4V) in medical applications. The corrosion resistance was evaluated utilizing potentiodynamic polarization curves (PPCs), electrochemical impedance spectroscopy (EIS), and open-circuit potential techniques (OCP), supplemented by XRD and SEM surface analysis. The T70Z20N7.5T2.5 alloy has the highest resistance to corrosion since it has the most stable passive state in addition to the lowest corrosion current ( Icorr = 11.8 μA cm− 2) and lowest CR (6.1 mpy) in comparison with that of T6A4V ( Icorr = 13.7 μA cm− 2, CR = 7.13 mpy) and Ti ( Icorr = 29.5 μA cm− 2, CR = 15.3 mpy). Furthermore, it was also looked at how different annealing temperatures (600, 800, and 1000 °C) and immersion times (one, two, and three weeks) affected the corrosion behavior of T70Z20N7.5T2.5. In comparison to the other samples, the T70Z20N7.5T2.5 alloy annealed at 800 °C demonstrated superior resistance to corrosion (the lowest Icorr = 1.53 × 10– 6 A cm− 2) and Ipass = 0.009 mA cm− 2. While that annealed at 1000 °C has the lowest resistance to corrosion (highest Icorr = 4.49 × 10– 5 A cm− 2 and Ipass = 0.611 mA cm− 2) as a result of the passive layer dissolution. The passive film is composed of an inner and outer oxide layer, according to the EIS measurements. Meanwhile, the PPCs data demonstrate that the resistance to corrosion of the alloy is higher without immersion than it is with immersion and for a shorter immersion time. It was found that the T70Z20N7.5T2.5 system consisted of α and β phases. An X-ray structural study indicated a mixture of body-centered cubic β-Ti and hexagonal close-packed α-Ti (main phase, with a grain size of about 5.35 nm). Therefore, among all the materials evaluated in this work, the T70Z20N7.5T2.5 alloy can be considered a promising material suitable for use as a biomaterial.