Orthorhombic to tetragonal polymorphic transformation of YTa3O9 and its inhibition through the design of high-entropy (Y0.2La0.2Ce0.2Nd0.2Gd0.2)Ta3O9
Orthorhombic to tetragonal polymorphic transformation of YTa3O9 and its inhibition through the design of high-entropy (Y0.2La0.2Ce0.2Nd0.2Gd0.2)Ta3O9
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DOI：
10.1016/j.jeurceramsoc.2022.03.005
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发表时间：
2022-03
影响因子：
5.7
通讯作者：
Hanwen Liu;Ling Liu;Huimin Xiang;Fu‐Zhi Dai;Xiaohui Wang;Muzhang Huang;C. Wan;Zhuang Ma;Yanbo Liu;Hezhang Li;Yanchun Zhou
中科院分区：
文献类型：
--
作者：
Hanwen Liu;Ling Liu;Huimin Xiang;Fu‐Zhi Dai;Xiaohui Wang;Muzhang Huang;C. Wan;Zhuang Ma;Yanbo Liu;Hezhang Li;Yanchun Zhou
为了探究相变机理，以Y2O3和Ta2O5粉体为原料，采用一步合成和1500℃烧结的一体化方法制备了YTa3O9。高温 XRD 图和拉曼光谱表明，YTa3O9 在 300–400 °C 时通过键长和角度的变化发生了从正交晶系到四方晶系的相变，从而导致热导率上升。为了抑制相变，设计了高熵(Y0.2La0.2Ce0.2Nd0.2Gd0.2)Ta3O9(HE RETa3O9)，并采用固态合成和烧结一体化方法在1550℃下合成。在四方结构 HE RETa3O9 中，高熵效应抑制了相变。此外，HE RETa3O9 表现出较低的导热率，并且其随温度升高的趋势得到缓解（1.69 W/m·K，1073 K）。良好的相稳定性、低热导率和与YSZ相当的断裂韧性使HE RETa3O9有望成为新型热障涂层材料。
To explore the mechanism of phase transformation, YTa3O9was prepared by an integrated one-step synthesis and sintering method at 1500 °C using Y2O3and Ta2O5powders as starting materials. High-temperature XRD patterns and Raman spectra showed that a phase transformation from orthorhombic to tetragonal took place in YTa3O9through the bond length and angle changes at 300–400 °C, which caused a thermal conductivity rise. To inhibit the phase transformation, a high-entropy (Y0.2La0.2Ce0.2Nd0.2Gd0.2)Ta3O9(HE RETa3O9) was designed and synthesized at 1550 °C using the integrated solid-state synthesis and sintering method. In tetragonal structured HE RETa3O9, phase transformation was inhibited by the high-entropy effect. Furthermore, HE RETa3O9exhibited low thermal conductivity, and its tendency to increase with temperature was alleviated (1.69 W/m·K, 1073 K). Good phase stability, low thermal conductivity and comparable fracture toughness to YSZ make HE RETa3O9promising as a new thermal barrier coating material.