Stabilization of carbonate hydroxyapatite by isomorphic substitutions of sodium for calcium
Stabilization of carbonate hydroxyapatite by isomorphic substitutions of sodium for calcium
复制标题
DOI：
10.1134/s0036023608020022
复制
发表时间：
2008-02-01
影响因子：
2.1
通讯作者：
Fomin, A. S.
中科院分区：
文献类型：
--
作者：
Barinov, S. M.;Fadeeva, I. V.;Fomin, A. S.
碳酸羟基磷灰石（CHA）是骨组织中矿物质成分的类似物。合成CHA是热不稳定的：当烧结成陶瓷时，它很容易分解并释放出碳氧化物。它的热稳定性已被研究的影响，旨在补偿可能的电荷不平衡引起的CO 32-基团的部分同构取代钠钙。调查工具是通过加热掺杂有0.4和0.8重量%钠的CHA样品产生的冷凝蒸气的热重分析和FTIR光谱。钠不会改善CHA的热稳定性：加热时的重量损失随着钠水平的增加而增加;碳氧化物的析出在较低温度下发生，并且更强烈。钠增强了B型缺陷（CO 32-> PO 43-取代）的产生;这些缺陷在化学上比AB型缺陷（CO 32-> PO 43-、OH-取代）更不稳定，AB型缺陷是无钠CHA的特征。
Carbonate hydroxyapatite (CHA) is an analogue of the mineral component of bone tissue. Synthetic CHA is thermally unstable: it readily decomposes with carbon oxide evolution when sintered to ceramics. Its thermal stability has been studied as affected by partial isomorphic substitution of sodium for calcium intended to compensate a possible charge imbalance induced by CO32- groups. Investigative tools were thermogravimetry and FTIR spectroscopy of the condensed vapor produced by heating CHA samples doped with 0.4 and 0.8 wt % sodium. Sodium does not improve the thermal stability of CHA: weight loss on heating increases with increasing sodium level; evolution of carbon oxides occurs at lower temperatures and more intensively. Sodium enhances the generation of B-type defects (CO32- -> PO43- substitutions); these defects are thermodynamically less stable than AB-type defects (CO32- -> PO43-, OH- substitutions), which are characteristic of sodium-free CHA.