Electrochemical formation of self-organized anodic nanotube coating on Ti-28Zr-8Nb biomedical alloy surface.

In recent years, Ti-Zr-Nb alloys have become increasingly attractive as biomedical implant materials. In the present communication, we report the formation of self-organized nanotube oxide layers on a Ti-28Zr-8Nb biomedical alloy surface in 1M (NH4)2SO4 containing 0.25M NH4F. The morphology of the nanotube layers (the diameter and the length) is affected by the electrochemical conditions used (applied potential and time). Under specific conditions oxide layers consisting of highly ordered nanotubes with a wide range of diameters and lengths can be formed, varying, respectively, from approx. 50 to 300nm and from approx. 500nm to 22microm. The present results are highly promising for this biomedical alloy, as the large surface area and the tunable nanoscale geometry of the surface oxide provide novel pathways for the interaction of the materials with biorelevant species, such as cells and proteins.