Influence of Hydrothermal Processing on the Structuring of Amorphous Strontium Hydroxyapatite

Strontium substituted hydroxyapatite is a biomaterial with high level of biocompatibility with improved cell proliferation from Sr ions in hydroxyapatite. The aim of this research is to study the effect of saturated steam pressure at elevated temperature on the transitions within amorphous strontium hydroxyapatite powder. Processing temperatures and times ranged from 90 to 150∘C for periods of 1, 3 and 6 hours, respectively. Powder was characterized by X-Ray Diffraction and Fourier Transformed Infrared Spectroscopy. The appearance of diffraction peaks in the X-ray diffraction pattern suggested that longer processing times were necessary to transform amorphous strontium hydroxyapatite to a higher crystallinity at lower temperatures. Transition from the amorphous to the crystalline state begins at 150∘C after an hour, at 120∘C after 3 hours, or at 110∘C after 6 hours. Infrared spectroscopy showed the characteristic phosphate absorption band and the presence of carbonate in the powder.     Keywords: hydrothermal processing, biomaterials, hydroxyapatite, material design, biocompatibilit