Corrosion resistance and biocompatibility of Ti-Ta alloys for biomedical applications

Corrosion resistance, wear resistance and biocompatibility of the studied Ti-Ta alloys with Ta contents of 10, 30 and 70 mass% together with the currently used metallic biomaterials pure titanium (Ti) and Ti-6Al-4V extra low interstitial (ELI) alloy were investigated for biomedical applications. Corrosion resistance was measured by an anodic polarization test using an automatic potentiostat in 5% HCl solution at 310 K. Wear resistance was evaluated using a pin-on-disk type friction wear test system with a load of 4.9 N at 310 K in a simulated body fluid (Ringer's solution), and biocompatibility was judged by evaluating the cyto-toxicity through MTT assay. The passive behaviors are observed for all the studied Ti-Ta alloys, and the TiO₂ passive films strengthened by the more stable Ta₂O₅ passive films result in improved corrosion resistance of the studied Ti-Ta alloys with increasing Ta content. All the studied Ti-Ta alloys are non-cytotoxic like pure Ti. The crystal structure shows little influence on the corrosion resistance and cyto-toxicity of the studied Ti-Ta alloys. The experimental results conform the expected excellent corrosion resistance and biocompatibility of the studied Ti-Ta alloys, which are better than or similar to those of pure Ti or Ti-6Al-4V ELI alloy used as standard biomaterials, suggesting their promising potential for biomedical applications.