abstract
The present study aimed at investigating the cosubstitution of two biologically important cations, namely Zn2+ and Sr2+, in the structure of beta-tricalcium phosphate (beta-TCP), a well-known resorbable biomaterial. The formation Zn2+ and Sr2+ cosubstituted beta-Ca(3)(PO(4))(2) has been ensured through aqueous coprecipitation technique that involves the addition of Zn2+ and Sr2+ containing precursors to partially replace Ca2+ in a calcium-deficient apatite composition during the synthesis, followed by heat treating the resultant apatites at 800 degrees C to form single-phase beta-Ca(3)(PO(4))(2). Five different concentrations of single or combined substitution of elements have been investigated and the results were compared with those of pure beta-TCP without any substituted Zn2+ and Sr2+. The obtained materials were characterized by X-ray diffraction, FT-IR, elemental analysis, and Rietveld refinement techniques. The transformation of deficient apatites to Zn2+ and Sr2+ cosubstituted beta-TCP occurred at 800 degrees C and well crystalline beta-TCP materials were formed at 1000 degrees C with the typical rhombohedral structure at hexagonal setting (space group R3c). The Rietveld refinement results revealed gradual decreases in the a-axis and c-axis lattice parameters with increasing concentration levels of Zn2+ and Sr2+ substituted in the lattice of beta-TCP. Zn2+ prefers to occupy the sixfold coordinated Ca (5) site whereas Sr2+ preferentially occupies the ninefold coordinated Ca (4) site of beta-TCP structure.
keywords
NEUTRON POWDER DIFFRACTION; CRYSTAL-STRUCTURE ANALYSIS; THERMAL-STABILITY; BONE-FORMATION; HYDROXYAPATITES; APATITES; SODIUM; RATS
subject category
Materials Science
authors
Kannan, S; Goetz-Neunhoeffer, F; Neubauer, J; Ferreira, JMF
our authors
acknowledgements
This work was financially supported by CICECO, University of Aveiro and GRICES-DAAD.