Structural characterization of nano-sized calcium deficient apatite powders.
Nano-sized calcium-deficient apatitic (CDHA) crystals with Ca/P ratios from 1.5 to 1.67 were synthesized using wet chemical method and of needle-like shape with 5-10 nm in diameter and 40-50 nm in length was observed. The structural environment of the Ca atoms in all the CDHA nano-crystals has been investigated using EXAFS, XANES and EELS. The results reveal that a maximum Fourier transform amplitude occurs at the apatite with a Ca/P ratio of 1.67 and the structural disorder increase following the sequence of 1.67>1.5>1.6>1.55. A similar phenomenon is also observed in both K-edge XANES and L(2,3)-edge ELNES in the Ca atom. The structural analysis further demonstrates that different chemical and biological properties among these CDHA nano-crystals with Ca/P ratio from 1.5 to 1.67 are primarily due to the effect of stoichiometry and non-stoichiometry as compared to the structural order-disorder.
Department of Materials Science and Engineering, National Chiao-Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan, ROC.
Sz-Chian
SC
Liou
San-Yuan
SY
Chen
Hsin-Yi
HY
Lee
Jong-Shing
JS
Bow
D001031:Apatites / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D008854:Microscopy, Electron; D036103:Nanotechnology; D017550:Spectroscopy, Fourier Transform Infrared
D001031:Apatites; D002118:Calcium