Inhibition effect of zirconium coating on calcium phosphate precipitation of titanium to avoid assimilation with bone

In order to control of the calcium phosphate precipitation of Ti in body fluid, which might result in assimilated bone re-facture during removal operation of implanted devices such as femoral nails and bone screws after healing, vacuum vapor deposition of Zr on Ti Substrate was carried out. The calcium phosphate precipitation was evaluated through the immersion test into the Hanks' solution. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were conducted to evaluate inhibition effect of coated Zr layer. Calcium phosphate particle were observed on the Ti with and without 90-mu thick Zr coated layer by SEM. On the other hand, on the specimens with 130-nm thick Zr coated layer and those of Zr sputter-coated, no calcium phosphate particle was observed. By the surface analysis of the specimens Zr sputter-coated, Ca was not identified. It was considered to form zirconium phosphate instead of calcium phosphate by immersion in the Hanks' solution. It was suggested that Zr coating technique can be applied to orthopedic devices to avoid re-fracture of bone by calcium phosphate precipitation during removal operation.