Formation of calcium-deficient hydroxyapatite from α-tricalcium phosphate
Formation of calcium-deficient hydroxyapatite from α-tricalcium phosphate
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DOI：
10.1016/s0142-9612(98)00131-8
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发表时间：
1998-12-01
期刊：
影响因子：
14
通讯作者：
Brown, PW
中科院分区：
文献类型：
--
作者：
TenHuisen, KS;Brown, PW
研究了α-Ca-3(PO4)(2)(α-TCP)生成Ca9HPO4(PO4)(5)OH(缺钙羟基磷灰石或CDHAp)动力学的影响因素。用等温量热法研究了恒温(30~75℃)和pH变化(37.4~70℃)下CDHAp的生成动力学，量热曲线由两个反应峰表征。计算了导致这些峰值的事件的激活能。得到的值分别为48.4和67.7kJ·mol(-1)，表明这两个事件的成核和生长机制。温度对生长速度有显著影响，随着温度的升高(30-75℃)，CDHAp的表面积(26.5-15.0m(2)g(-1))减小。水解温度与CDHAp比表面积呈线性关系。随着反应温度的升高，CDHAp的形貌呈片状，结晶变得更加规则。当与水混合时，pH迅速上升，这表明最初使用的合成方法并未完全消除α-Ca-3(PO4)(2)中的微小组成变化。PH值的快速升高延缓了后续反应。在α-磷酸三钙合成过程中，通过延长高温烧成时间，消除了这一影响。(C)1998爱思唯尔科学有限公司。保留所有权利。
This study investigated the factors influencing the kinetics of Ca9HPO4(PO4)(5)OH (calcium deficient hydroxyapatite or CDHAp) formation from alpha-Ca-3(PO4)(2) (alpha-TCP). The kinetics of CDHAp formation were investigated by isothermal calorimetry at constant temperatures ranging between 30 and 75 degrees C and by changes in pH at 37.4 and 70 degrees C. The calorimetric curves were characterized by two reaction peaks. Activation energies were calculated for the events resulting in these peaks. Values obtained were 48.4 and 67.7 kJ mol(-1), respectively, indicating nucleation and growth mechanisms for both events. Temperature had a significant effect on the growth rate as indicated by a decrease in surface area (26.5-15.0 m(2) g(-1)) of the CDHAp with increasing temperature (30-75 degrees C). A linear relationship between hydrolysis temperature and CDHAp surface area was observed. The morphology of the CDHAp was plate-like and the crystallites became more regular as the reaction temperature was increased. A rapid elevation in pH upon mixing with water indicated the synthesis method initially used did not entirely eliminate slight compositional variations within the alpha-Ca-3(PO4)(2). Rapid elevation in pH retarded subsequent reaction. This effect was eliminated by increasing the duration of high-temperature firing during alpha-TCP synthesizing. (C) 1998 Elsevier Science Ltd. All rights reserved.