Corrosion-resistant Ti–Zr–Sn–Ta–Mo alloys with enhanced passivation for orthopedic implant applications

Hip joint degeneration is a major cause of disability worldwide, driving the need for durable implant materials with superior corrosion resistance. Titanium (Ti) alloys are widely used in orthopedic applications, yet long-term performance can be limited by electrochemical degradation in physiological environments. In this work, the influence of Mo and Ta additions on the corrosion behavior of Ti-10Zr-2Sn alloys was investigated. Three compositions-Ti-10Zr-2Sn-2Ta-6Mo, Ti-10Zr-2Sn-4Ta-4Mo, and Ti-10Zr-2Sn-6Ta-2Mo-were fabricated and evaluated in 3.5% NaCl solution using current-time response, electrochemical impedance spectroscopy, and cyclic polarization. All alloys exhibited improved passivation with extended exposure time (1-48 h), attributed to the growth of protective oxide layers. Among them, Ti-10Zr-2Sn-4Ta-4Mo demonstrated the highest polarization resistance and stability, with no evidence of pitting observed by SEM/EDS. These findings highlight the promise of tailored Ti-Zr-Sn-Ta-Mo alloys for orthopedic implants, offering improved corrosion resistance and potentially longer clinical lifetimes.