Influence of microwave processing and sintering temperature on the structure and properties of Sr/Zr doped hydroxyapatite

Abstract

Abstract Among the different cations that are substituted to modify the properties of calcium hydroxyapatite, Sr and Zr have gained interest because of their effect on bone formation and mechanical properties, respectively. In the present work, Sr and Zr substituted hydroxyapatite, Ca9·39Zr0·11Sr0·5(PO4)6(OH)2 are synthesized by conventional and microwave sintering at different temperatures. The effect of different sintering techniques and temperatures are investigated on the structural and morphological properties of as-synthesized samples. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) is used to study the variation in structural properties and scanning electron microscopy (SEM) is used to investigate the morphology with the variation in sintering conditions. The changes in lattice parameters clearly show that Sr and Zr are incorporated into hydroxyapatite lattice. Microwave sintered samples retain the higher amount of hydroxyapatite and experience higher density levels as compared to conventional sintering. As compared to conventional sintering, the grain size is more uniform and low percentage of secondary phase is observed in microwave sintered sample.