Low-Temperature Synthesis Approach for Calcium Hydroxyapatite Coatings on Titanium Substrate

Abstract

In this study, a low-temperature synthetic approach was developed for the fabrication of calcium hydroxyapatite (CHAp) coatings on a titanium substrate. The titanium substrates were first coated with CaCO3 by a spin-coating technique using a sol–gel chemistry approach, and the obtained product was transformed into CHAp during a dissolution–precipitation reaction. The phase purity and structural and morphological features of the obtained CHAp coatings were evaluated by X-ray diffraction (XRD) analysis, FTIR spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and using a 3D optical profilometer. It was demonstrated that almost-single-phase CHAp formed on the titanium substrate with a negligible number of side phases, such as Na2HPO4 (starting material) and TiO2. In the Raman spectrum of the CHAp coating, the peaks of phosphate group vibrations were clearly seen. Thus, the obtained results of Raman spectroscopy correlated well with the results of X-ray diffraction analysis. The corrosive behaviour of CHAp coatings on a titanium substrate was also evaluated using electrochemical methods. It was found that the corrosion resistance of titanium coated with CHAp increased significantly. These CHAp thin films may be potential candidates for use in not only in regenerative medicine but also in the development of different sensors.