当前位置: X-MOL 学术J. Phase Equilib. Diffus. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
An Insight from the CALPHAD Approach: How to Control the LaMnO3 Perovskite Formation Via the Molten Salt Synthesis
Journal of Phase Equilibria and Diffusion ( IF 1.5 ) Pub Date : 2021-06-21 , DOI: 10.1007/s11669-021-00895-9
Yu Zhong , Shadi Darvish , Benjamin Levitas , Tauny Tambolleo , Srikanth Gopalan , Mei Yang

LiCl-KCl molten salt has been used as a reaction medium to synthesize various perovskite materials from oxide precursors. However, it was observed that temperature, p(O2), precursor mix ratio, etc., greatly affected the perovskite stoichiometry, phase stability, crystal structure, and the formation of various impurities (secondary phases). Thermodynamics and kinetics involved in the synthesis are complicated. Guidance from thermodynamic modeling is thus needed to control the formation of the perovskites. In the present work, for the first time we use the CALculation of PHAse Diagram (CALPHAD) approach to develop a perovskite-molten salt thermodynamic database, which is used to understand the phase equilibrium between the molten salt, precursor oxides, and the resulting LaMnO3 (LMO) perovskite. Especially, the effects of temperature, La2O3 and Mn2O3 precursor ratio, and p(O2) on the LMO phase stability were predicted. Pseudo-ternary isothermal sections were generated, which successfully predicted the coexistence of LaMnO3 and the impurity, LaOCl. Meanwhile, the molten salt thermodynamic experiments were designed and carried out to verify La and Mn's solubilities in LiCl-KCl molten salt and thermodynamic equilibria in the La-Mn-O-Li-K-Cl system. The CALPHAD predictions were in accord with the experimental observations.



中文翻译:

CALPHAD 方法的见解:如何通过熔盐合成控制 LaMnO3 钙钛矿的形成

LiCl-KCl 熔盐已被用作反应介质,以从氧化物前体合成各种钙钛矿材料。然而,观察到温度、p(O 2 )、前体混合比等对钙钛矿的化学计量、相稳定性、晶体结构和各种杂质(第二相)的形成有很大影响。合成中涉及的热力学和动力学是复杂的。因此需要来自热力学模型的指导来控制钙钛矿的形成。在目前的工作中,我们首次使用 PHA 酶图计算 (CALPHAD) 方法来开发钙钛矿-熔盐热力学数据库,该数据库用于了解熔盐、前体氧化物和由此产生的 La​​MnO 之间的相平衡3(LMO) 钙钛矿。特别地,预测了温度、La 2 O 3和Mn 2 O 3前驱体比例以及p(O 2 )对LMO相稳定性的影响。生成了伪三元等温截面,成功预测了 LaMnO 3和杂质 LaOCl 的共存。同时,设计并进行了熔盐热力学实验,验证了 La 和 Mn 在 LiCl-KCl 熔盐中的溶解度和 La-Mn-O-Li-K-Cl 体系中的热力学平衡。CALPHAD 的预测与实验观察一致。

更新日期:2021-06-21
down
wechat
bug