The bioactivity of enhanced Ti-32Nb-5Zr alloy with anodic oxidation and cyclic calcification

Nanotubes form highly compact structures of small diameter tubes in between relatively larger diameter tubes, and have a structure of hollow tubes with connected outer walls. An even calcium phosphate layer was formed on the surface of the nanotube layer by alternative immersion treatment (AIT). The precipitated calcium phosphate formed a bite with the surface of the vesicular structure and was combined as penetration occurred inside the nanotubes. Hydroxyapatite (HAp) precipitation of Ti-32Nb-5Zr alloy treated with AIT rapidly accelerated under the environment of simulated body fluid. When implanted into the tibias of a rat, the bonding strength of bone and the amount of newly formed bone were greatly enhanced. This demonstrates that the bioactivity of β-type Ti-32Nb-5Zr alloy could be enhanced through the formation of a TiO₂ layer and cyclic calcification in a solution containing phosphate and calcium ions.