Ultraviolet-accelerated formation of bone-like apatite on oxidized Ti–24Nb–4Zr–7.9Sn alloy

Abstract

A novel method has been developed to rapidly deposit bone-like apatite with the assistance of ultraviolet (UV) light irradiation on the nanostructured titania in the simulated body fluid (SBF). The process has three main steps: Ti–24Nb–4Zr–7.9Sn alloy was heated at 650°C for 3 h, UV-light illumination in air for 4 h and soaking in the SBF for 3 d. A titania coating consisted of main rutile formed on the thermal oxidized Ti–24Nb–4Zr–7.9Sn alloy. The UV not only converted the rutile surface from hydrophilic to hydrophobic but also stimulated high surface activity. After 4 h UV illumination, the contents of Ti³⁺ and hydroxyl groups on the oxidized sample were increased, while that of lattice O decreased. After 3 d of soaking in the SBF, a compact and uniform layer of carbonated hydroxyapatite (CHA) particles was formed on the UV-illuminated rutile surface whereas there was a few of HA to be viewed on the surface of as-oxidized Ti–24Nb–4Zr–7.9Sn alloy. Our study demonstrates a simple, fast and cost-effective technique for growing bone-like apatite on titanium alloys.

Keywords

Ti–24Nb–4Zr–7.9Sn alloy / thermal oxidation / UV illumination / rutile / bone-like apatite