Synthesis and characterization of cadmium-calcium hydroxyapatite solid solutions
A series of cadmium-calcium hydroxyapatite solid solutions was prepared by an aqueous precipitation method. By various means, the characterizations confirmed the formation of continuous solid solutions over all ranges of Cd/(Cd+Ca) atomic ratio. In the results, both lattice parameters a and c display slight deviations from Vegard’s rule when the Cd/(Cd+Ca) atomic ratio is greater than 0.6. The particles change from smaller acicular to larger hexagonal columnar crystals as the Cd/(Cd+Ca) atomic ratio increases from 0–0.60 to 0.60–1.00. The area of the phosphate peak for symmetric P-O stretching decreases with the increase in Cd/(Cd+Ca) atomic ratio, and the peak disappears when the Cd/(Cd+Ca) atomic ratio is greater than 0.6; the two phosphate peaks of P-O stretching gradually merge together for the Cd/(Cd+Ca) atomic ratio near 0.60. These variations can be explained by a slight tendency of larger Cd ions to occupy M(2) sites and smaller Ca ions to prefer M(1) sites in the structure.
Keywordshydroxyapatite solid solutions cadmium calcium substitution
Unable to display preview. Download preview PDF.
- A. Nounah, N. Maroufi, Y. Ait Ichou, J.L. Lacout, and J.M. Savariault, X-ray diffraction study of cadmium hydroxyapatite, J. Phys. IV, 123(2005), No. 3, p. 251.Google Scholar
- H.Y. Xu, Y. Liu, M.S. Peng, Z. Wu, and J. Ding, Crystal- and thermal-chemistry of cadmium-calcium hydroxyapatite solid solution whiskers synthesized by solution method, J. Mineral. Petrol., 29(2009), No. 2, p. 5.Google Scholar