Electrochemical Anodization of β-Ti35Nb5Ta Alloy for Enhanced Surface and Mechanical Properties

This study investigates the electrochemical anodization of the β-type Ti35Nb5Ta alloy as an integrated strategy to improve mechanical compatibility, surface functionality, and nanoscale electrical performance for biomedical applications. The alloy, produced via arc melting, hot forging, and solution treatment at 900 °C, developed a fully stabilized β-phase microstructure with coarse equiaxed grains, as confirmed by XRD, SEM, and OM. Electrochemical anodization in 0.30% HF at 20 V for 1 hour resulted in the formation of self-organized TiO₂ nanotubes with a uniform morphology, strong adhesion, and a grain-dependent distribution. Surface analyses by AFM and nanoindentation revealed clear trends of increased roughness and stiffness in the anodized regions, while conductive AFM and Kelvin probe microscopy indicated enhanced electrical activity at grain surfaces. These improvements were attributed to the synergistic effect of Nb and Ta in modulating Ti and O vacancies and controlling defect chemistry. The findings highlight a novel and practical approach for engineering nanostructured oxide layers with tunable mechanical and electronic properties, offering a promising pathway for enhancing osseointegration and long-term implant performance.