Hydration of tetracalcium phosphate
Hydration of tetracalcium phosphate
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磷酸四钙的水合
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
P. Brown
中科院分区：
文献类型：
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作者：
R. I. Martin;P. Brown
水合磷酸四钙在25至70°C的温度下在水溶液中等温反应时，仅在几个小时内放出可测量的热量。水合反应是不完全的，并且磷酸四钙是通过X射线衍射分析检测到的唯一结晶固体。磷酸四钙水化反应的表观活化能为36 kJ/mol。该量级的活化能指示界面控制的反应。与最初受界面控制的许多水合反应一样，水合产物层积聚在水合表面上，并且随后的水合变得受扩散控制。与这种机理路径一致，用氢氧化钙接种降低了最大放热速率和反应总热，而用羟基磷灰石接种增加了总放热。当磷酸四钙浆料连续搅拌一段较长的时间时，可以实现完全水合。
Hydrating tetracalcium phosphate evolves measurable heat for only a few hours when reacted isothermally in aqueous solution at temperatures between 25 and 70°C. The hydration reaction is incomplete, and tetra calcium phosphate is the only crystalline solid detected by X-ray diffraction analysis. The apparent activation energy of tetracalcium phosphate hydration is 36 kJ/mol. An activation energy of this magnitude is indicative of an interfacially controlled reaction. As with many hydration reactions, which are initially interfacially controlled, a layer of hydration product accumulates on the hydrating surfaces, and subsequent hydration becomes diffusionally controlled. Consistent with such a mechanistic path, seeding with calcium hydroxide reduces both the maximum rate of heat evolution and the total heat of reaction , while seeding with hydroxyapatite increases the total heat evolved. Complete hydration may be achieved when a tetracalcium phosphate slurry is continuously agitated for an extended period....