The metastable and stable equilibria of a precipitation in the biomimetic system Simulated Body Fluid (SBF)–CaCl₂–K₂HPO₄–KOH–H₂O were modeled in the pH region 3–7 at a Ca/P molar ratio of 1 using a thermodynamic approach. Saturation indices (SI) of the solid phases were calculated and used to prognose the salt precipitation/dissolution processes. At рН < 4, the solutions are undersaturated (SI < 0) in respect of all solid phases; co‐precipitation of dicalcium phosphate dihydrate (DCPD) and hydroxyapatite (HA) occurs at рН 4 while at рН > 4 the stable phase is DCPD but the number of other co‐precipitated solid phases increases. This result is associated with the increase in HPO₄²⁻, CaHPO₄⁰, and KНРО₄⁻ species in the studied solution. The phase transformations of five model DCPD‐based calcium phosphate precursors in three simulated body fluids differing in their composition, to more stable octacalcium phosphate and hydroxyapatite was thermodynamically prognosed and experimentally confirmed by kinetic studies, as well as by chemical, XRD, SEM, and IR methods.

中文翻译：

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模拟体液电解质溶液中磷酸二钙二水合物的沉淀和相变：热力学建模和动力学研究。

仿生系统模拟体液 (SBF)–CaCl ₂ –K ₂ HPO ₄ –KOH–H ₂ O 中沉淀的亚稳态和稳定平衡在 pH 区域 3–7 中建模，Ca/P 摩尔比为 1使用热力学方法。计算固相的饱和指数 (SI) 并用于预测盐沉淀/溶解过程。在 рН < 4 时，溶液对于所有固相都是不饱和的（SI < 0）；二水合磷酸二钙 (DCPD) 和羟基磷灰石 (HA) 的共沉淀发生在 рН 4 而在 рН > 4 稳定相是 DCPD 但其他共沉淀固相的数量增加。该结果与 HPO ₄ ²⁻、CaHPO₄ ⁰和 KНРО ₄ ^-研究溶液中的物种。三种模拟体液中基于 DCPD 的五种模型磷酸钙前体的相变，通过热力学预测并通过动力学研究以及化学、XRD、SEM 和红外方法。