Structural and compositional characterization of ion beam sputtered hydroxyapatite thin films on Ti-6A1-4v

Abstract

Ion Beam Sputtering (IBS) technique has been used to prepare a series of hydroxyapatite (HA) thin films on Ti and Ti alloy substrates for biomedical application. We report the effect of Post Deposition Heat Treatment (PDHT) on the structural, compositional and surface characteristics of HA films deposited on TÌ-6A1-4V. The films underwent PDHT for 2 h at 300, 400, 500 and 600°C under air environment. After PDHT, the structure and the chemical composition of the films were characterized using Rutherford Backscattering Spectrometry (RBS), X-ray Diffraction (XRD), Fourier transform infrared absorption spectrometry (FTIR) and Scanning Electron Microscopy (SEM). The results showed that the crystallinity of HA increased with temperature. However, SEM results revealed that some cracks were observed if the temperature of PDHT was higher than 600°C. FTIR measurements showed that the existence of hydroxyl and phosphate bands in all films increased with temperature. RBS analysis indicated that the as-deposited films had a low Ca/P ratio which increased to stoichiometric value with increasing PDHT temperature. From this study we suggest that 600°C is probably the best PDHT temperature to obtain a better characterization and surface properties of HA film produced by IBS. It can also be concluded that IBS can be used as an alternative method for deposit HA film on titanium alloy substrate.