亚稳相对表面张力和从熔体中选择固体多晶型物的隐藏作用
Hidden role of metastable phases on surface tension and in the selection of solid polymorphs from melt
摘要：
当一种固体在特定温度下从熔体中沉淀出来时，它优先形成于另一种固体，这通常是通过调用热力学和动力学控制之间的竞争来解释的。然而，由于缺乏相关表面张力项的精确值，无法建立定量理论。受两个稳定相之间的界面被中间级的多个亚稳相润湿可以显著降低表面张力的观察的启发（Kirkpatrick-Thirumalai-Wolynes（KTW），Phys.Rev.A1989，40（2），1045; Santra等人，J. Phys. Chem. B，2013，117，13154），我们开发了一种基于Landau-Ginzburg型自由能泛函的统计力学方法来计算在N个亚稳相存在下两个稳定相之间的表面张力。简单的模型计算表明，两个共存的稳定相（熔体和稳定的结晶形式）之间的表面张力显着依赖于数量，相对深度和安排的亚稳相的自由能极小值，除了核的大小。我们提供了一个解释的快速消失的多晶型物（QDPMs），往往融化回液体（或溶胶）相。结果表明，我们的模型系统可以描述一些方面的固体形成在真正的多晶型系统，如磷酸盐和沸石。
英文摘要：
The preferential formation of one solid over the other, as it precipitates out from the melt at specific temperatures, is often explained by invoking a competition between thermodynamic and kinetic control. A quantitative theory, however, could not be developed because of the lack of accurate values of relevant surface tension terms. Motivated by the observations that wetting of the interface between two stable phases by multiple metastable phases of intermediate order can reduce the surface tension significantly (Kirkpatrick-Thirumalai-Wolynes (KTW), Phys. Rev. A 1989, 40 (2), 1045; Santra et al., J. Phys. Chem. B, 2013, 117, 13154 ), we develop a statistical mechanical approach based on a Landau-Ginzburg type free energy functional to calculate the surface tension between two stable phases in the presence of N number of metastable phases. Simple model calculations are performed that show the surface tension between two coexisting stable phases (melt and the stable crystalline forms) depends significantly on the number, relative depths and arrangements of the free energy minima of the metastable phases, in addition to the size of the nucleus. We provide an explanation of the quickly disappearing polymorphs (QDPMs) that often melt back to the liquid (or, the sol) phase. It is shown that our model systems could describe some aspects of solid formation in real polymorphic systems, like phosphates and zeolites.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
