A new biocompatible coating layer applied on titanium substrates using a modified zinc phosphatizing method

A new biocompatible coating layer was successfully prepared on titanium (Ti) substrate. by hydrothermal treatment in an acidic zinc phosphate solution at 250 °C for 8 h or longer time. Elemental analysis of the crystalline coating layer showed the existence of Zn, Ti and P with an approximate atomic ratio of 0.27:0.86:1. From X-ray diffractometry, the crystalline coating structure could be indexed as tetragonal lipscombite-like structure (space group, I41/amd) with lattice parameters of a = 0.5173 nm and c = 1.3017 nm and was identified as a new zinc titanium phosphate (Ti–Zn–PO4) phase. The interfacial fracture strength between substrate and Ti–Zn–PO4 coating layer prepared at 250 °C for 10 h was higher than the measured adhesive strength value (48.3 ± 9.2 MPa). In vitro cell study indicated that cell proliferation results for Ti–Zn–PO4 layer were much better than those for non-coated Ti substrates. We therefore concluded that the Ti–Zn–PO4 coating might be useful for biomedical applications such as Ti implants.