Surface and Coatings Technology, cilt.520, 2026 (SCI-Expanded, Scopus)
Titanium is widely used as a biomaterial, but it suffers from poor tribological properties. Additionally, due to the stress shielding effect caused by the elastic modulus mismatch between the titanium implant and the bone, materials closer to bone elasticity have gained prominence. This study evaluates glow discharge plasma oxidation on the structural, mechanical, tribological, electrochemical, and biological properties of beta (β) type Ti45Nb and alpha+beta (α + β) type Ti6Al7Nb alloys for potential biomedical applications. Treatments were conducted at 600 °C, 700 °C, and 800 °C for 1 and 4 h. Phase analysis revealed rutile-TiO2 dominated oxide layer formation and oxygen diffusion into the substrate, enhancing surface hardness. Tribological tests showed a significant reduction in wear rate for both alloys, particularly at lower oxidation temperatures. Electrochemical analysis in simulated body fluid demonstrated some improvement on corrosion resistance and passivation for oxidized samples. Tribocorrosion tests confirmed the synergistic effect of wear and corrosion, with Ti45Nb showing superior performance. Biocompatibility and genotoxicity assays suggested that high temperature oxidation may reduce cell viability. Overall, low temperature plasma oxidized Ti45Nb, with its low elastic modulus and enhanced tribocorrosion resistance, emerges a promising candidate for load-bearing orthopedic implants.