Papers by Keyword: Precipitation Route

Abstract: The aim of this work was to evaluate the effect of precursor materials used in the synthesis on the Sr incorporation levels into the hydroxyapatite (HAp) lattice and to characterize the synthesis products. HAp powders containing various amounts of Sr were synthesized through three different precipitation routes. In all cases, the as-synthesized products were found to be pure HAp. However, atomic absorption spectrometry analysis showed that by reacting orthophosphoric acid with calcium hydroxide and strontium hydroxide, as well as by reacting diammonium hydrogen phosphate with calcium nitrate tetrahydrate and strontium nitrate a significant proportion of the Sr added, did not substitute into the HAp lattice. X-ray diffraction analysis revealed that the effect of substituting relatively high amounts (up to 3.69 ± 0.37 wt.%) of Sr into the HAp lattice was to decrease the cristallinity. Brunauer-Emmett-Teller (nitrogen absorption) analysis showed that the incorporation of Sr reduced particle sizes of the precipitated HAp products. Contrary, scanning electron microscopy revealed that the incorporation of Sr increased length of the precipitated needle-like particles.

Abstract: The synthetic hydroxyapatite is a very useful material for numerous applications in medicine as a biomaterial. One of the most economic manufacturing process is the precipitation route. In the present work, synthetic hydroxyapatite was prepared using the precipitation route, starting with aqueous solutions of calcium nitrate (Ca(NO3).4H2O ) and ammonium phosphate (H2(PO4)NH4). The effects of physical-chemical variables such as pH, temperature, time of agitation, ageing time and heat treatment of the mixture were evaluated. The characterization of the samples obtained in different conditions made possible to conclude about the optimal values of the studied variables for the synthesis of this material in laboratory conditions.