In-situ construction of the nanostructured TiO2/TiN composite films by induction heat treatment: Improved mechanical, corrosion, and biological properties

To meet the requirements for good mechanical properties, corrosion resistance, and osseointegration of human hard tissue substitutes and prostheses, a bioactive and stable surface is essential. In this work, in-situ construction of a TiO 2 /TiN composite film on titanium is achieved by induction heating at a high temperature under the O 2  + N 2 atmosphere. Furthermore, the surface of the composite film contains abundant oxygen vacancies, which is demonstrated by X-ray photoelectron spectroscopy (XPS) analysis. Transmission electron microscopy (TEM) and focus ion beam (FIB) milling technology are used to further study the cross-sectional microstructure and composition, revealing the formation mechanism of the composite film. The results of the nanoindentation and electrochemical test show that the hardness and corrosion rate of the composite film are 3.45 and 0.2 times that of titanium respectively. Moreover, the composite film is favorable for the deposition of hydroxyapatite in simulated body fluid (SBF). The results of the in vitro cellular experiments demonstrate that the composite film significantly promotes the adhesion, proliferation, and differentiation of BMSCs. Overall, the composite film is desirable for its improved biocompatibility, corrosion resistance, and mechanical properties, enabling it to have potential applications in the biomedical field.