Effect of TiH2 intermediate on the structure and properties of TiO2 coating induced on titanium by induction heating and its multifunctional mechanism

Highlights: • Induction heating (IH) combined with acid etching (AE) was used for Ti treatment. • TiH₂ produced in the AE process has a significant effect on the formation of TiO₂. • The coating exhibit excellent capacity of inducing hydroxyapatite formation in SBF. • The formation mechanism of the coatings formed by IH and AE + IH were studied. Pure titanium (Ti) implants often exist problems such as corrosion and wear in the clinical application. Surface modification is vital to improve the stability and bioactivity of Ti. Induction heating (IH) has attracted increasing attention as a potential surface modification method. In this study, two methods of IH and the combination of acid etching (AE) and IH (AE + IH) were used to fabricate a stable bioactive coating on Ti. The effects of AE and IH on the microstructures, phase composition, properties, and the formation mechanism of the coatings were investigated. Results show that the coatings formed by the two methods comprise crystalline rutile TiO₂ with different crystal shapes. The AE is important in determining the crystal structure of the coatings. Compared with the TiO₂ formed by IH, the TiO₂ coating formed by AE + IH is more compact and has smaller grains. The formation mechanism of different coatings can be attributed to the influence of TiH₂ formed by AE on IH treatment. The rutile TiO₂ coatings with different crystal shapes can significantly improve the corrosion resistance and wear resistance of Ti, and the coatings have good ability to induce the formation of HA in SBF.