Thermochemistry and phase stability of the polymorphs of yttrium tantalate, YTaO4
Thermochemistry and phase stability of the polymorphs of yttrium tantalate, YTaO4
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DOI：
10.1016/j.jeurceramsoc.2020.10.039
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发表时间：
2021-02-01
影响因子：
5.7
通讯作者：
Navrotsky, Alexandra
中科院分区：
文献类型：
--
作者：
Lepple, Maren;Ushakov, Sergey V.;Navrotsky, Alexandra
实验研究了YTaO4三种与弗格森铁矿相关的多晶M′、M和T的热力学参数及其相稳定性。关于M相和M′相相对稳定性的争论得到了解决，并表明化合物在熔化前不会转变为立方多晶。采用高温氧化物熔体溶液量热法测定了M和M′的生成焓，并测定了热容和热含量。用差热分析法测定了M′到T′相变的焓。利用高温x射线衍射和热分析证明了T相在2090℃熔化前的稳定性。它的聚变焓是用落抓式量热法测定的。本研究评估的YTaO4的热力学性质使其多晶态和相关材料系统的热力学建模具有重要的技术意义。
Thermodynamic parameters of the three fergusonite-related polymorphs M', M and T of YTaO4 and their phase stabilities were investigated experimentally. The debate on the relative stability of the M and M' phases was resolved, and it was shown that the compound does not transform to a cubic polymorph prior to melting. The enthalpies of formation of M and M' were determined using high temperature oxide melt solution calorimetry, and the heat capacities and heat contents were measured. The enthalpy of the M' to T phase transition was measured by differential thermal analysis. The stability of the T phase up to its melting at 2090 degrees C was demonstrated using high temperature X-ray diffraction and thermal analysis. Its enthalpy of fusion was determined using drop-and-catch calorimetry. The thermodynamic properties of YTaO4 assessed in this study enable the thermodynamic modeling of its polymorphs and related materials systems of technological importance.