Synthesis and characterization of strontium-based hydroxyapatites doped with erbium

In this thesis, the main purpose is to study the effects of strontium (Sr) and erbium (Er) dopants on the characteristic properties of hydroxyapatite (HAp). The HAp samples with fixed amount of Sr 0.35 at% and Er with various amounts of 0, 0.35, 0.70, 1.05, and 1.40 at % were synthesized by using wet chemical method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, differential thermal analysis (DTA), as well as in vitro biocompatibility analysis. In addition, the density of states (DOS) and band structures were investigated theoretically. In all samples, single-phase of HAp was detected. For the two different methods, the crystallinity percentage of the samples was estimated to be 89% or more. The crystallite sizes of the samples were computed to be in the range of 29-34 nm for Scherrer method, and 25-42 nm for Williamson-Hall method. DTA investigations revealed that all samples in temperature range from 25 °C to 1000 °C exhibited thermal stability. EDX results indicated that Ca-deficiency has occurred with increase in Er amount. No significant change was observed in the morphology of the samples. Additionally, is was found that the band structures turned to tightening with an increase in Er concentration from the theoretical study results.