Title: | Transformation mechanism of different chemically precipitated apatitic precursors into beta-tricalcium phosphate upon calcination |
Authors: | Liou, SC Chen, SY 材料科學與工程學系 Department of Materials Science and Engineering |
Keywords: | Ca-deficient apatite;beta-tricalcium phosphate;JMA equation;transformation kinetics |
Issue Date: | 1-Dec-2002 |
Abstract: | The Ca-deficient apatite (CDHA) was prepared from the precursors of (CH3COO)(2)Ca - xH(2)O, Ca(NO3)(2).4H(2)O and H3PO4, (NH4)H2PO4 to investigate the transformation mechanism of beta-tricalcium phosphate (beta-TCP). X-ray diffraction analysis shows that the development of beta-TCP is not via direct reaction between Ca and P for all the different combinations between Ca and P precursors. The activation energy of beta-TCP formation with (NH4)H2PO4 as precursor was higher than that with H3PO4. Following the Johnson-Mehl-Avrami equation, the reaction kinetics of beta-TCP phase formation is found one-dimension growth with interface-controlled and diffusion controlled growth depending on the annealing temperature. There exists a transition between 750 degreesC and 825 degreesC, and the transition rate from interface-controlled to diffusion-controlled growth is precursor-dependent. (C) 2002 Elsevier Science Ltd. All rights reserved. |
URI: | http://dx.doi.org/10.1016/S0142-9612(02)00198-9 http://hdl.handle.net/11536/28346 |
ISSN: | 0142-9612 |
DOI: | 10.1016/S0142-9612(02)00198-9 |
Journal: | BIOMATERIALS |
Volume: | 23 |
Issue: | 23 |
Begin Page: | 4541 |
End Page: | 4547 |
Appears in Collections: | Articles |
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