High-entropy thermal barrier coating of rare-earth zirconate: A case study on (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Zr2O7 prepared by atmospheric plasma spraying

Polysubstituted High-Entropy [LaNd](Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 Perovskites: Correlation of the Electrical and Magnetic Properties

“…Earlier researchers initially studied simple oxide compounds based on divalent metals (Mg, Co, Ni, Cu and Zn, for example, in [ 22 , 27 , 28 ]) or trivalent metals [ 30 , 31 ]. However, their interest was quickly attracted by HEO compounds with a more complex crystal structure than systems formed only by oxides of tri- or bi-valent metals [ 32 , 33 , 34 , 35 , 36 ]. Phases of high-entropy oxides with a spinel-like crystal structure were obtained in [ 37 , 38 ].…”

Interfacial Structure and Physical Properties of High-Entropy Oxide Coatings Prepared via Atmospheric Plasma Spraying

“…Currently, extensive studies are being conducted to develop a suitable alternative to 8YSZ [2,16,17]. These research efforts have led to the discovery of new materials with enhanced thermal barrier properties [18].…”

“…HEOs have been demonstrated to possess many exotic properties including thermoelectric properties, wear resistance, and corrosion resistance, and their possible applications include catalysts and batteries, among others. In particular, recent studies have demonstrated that forming a high-entropy solid solution is an effective method for improving the thermal insulation properties of thermal barrier materials [16,32,33]. For example, high-entropy (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 Zr 2 O 7 exhibits a low room-temperature thermal conductivity of 0.76 W/m•K [16].…”

“…In particular, recent studies have demonstrated that forming a high-entropy solid solution is an effective method for improving the thermal insulation properties of thermal barrier materials [16,32,33]. For example, high-entropy (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 Zr 2 O 7 exhibits a low room-temperature thermal conductivity of 0.76 W/m•K [16]. Wright et al [34] investigated 22 compositionally complex rare-earth zirconates and proposed size disorder as a descriptor for predicting thermal conductivity in these ceramic materials.…”

Study on the Solid Solution Structures of High-Entropy Ceramics by Transmission Electron Microscopy

“…高熵概念来源于高熵合金， 它以多元组分固溶来增加构型熵从而获得固溶体相结构上的 稳定。高熵会带来热力学上的高熵效应、结构上的晶格畸变效应、动力学上的迟滞扩散效应 以及性能上的"鸡尾酒"效应 [1] ，将高熵概念引入到陶瓷材料的研究已受到越来越多的关注。 自 2015 年 Rost 等 [2] 发现(MgNiCoCuZn)O 高熵氧化物陶瓷中熵能驱动多相和单相之间的可 逆变化之后，高熵氧化物 [3][4][5][6][7] 、 高熵硼化物 [8][9][10][11] 、碳化物 [12][13][14][15] 、硅化物 [16][17][18] 、MAX 相 [19][20] 、 阴离子高熵陶瓷 [21] 及高熵陶瓷基复合材料 [22][23][24][25] 等相关研究陆续被报道。过渡金属碳化物和 硼化物具有高熔点、高硬度、优异的高温力学性能和化学稳定性，被广泛应用于航空航天领 域 [26][27][28] ，并 在核工业领域具有良好的应用前景 [29][30] 。面对高温、高应力、强辐照和强腐蚀等 极端工作环境对性能的要求，通过高熵设计来提高陶瓷材料的性能是目前研究的热点。 有研究报导，高熵碳化物(TaHfZrNb)C 陶瓷在高温(1400 ℃和 1600 ℃)下的稳态蠕变 速率约为其中任意组成元素的二元碳化物陶瓷 90%，具有更高的抗高温蠕变特性 [31] 。高熵 碳化物(HfTaZrNb)C 陶瓷 [32] 以及高 熵 二 硼 化 物 (HfZrTaCrTi)B2 、 (HfMoZrNbTi)B2 、 (HfMoTaNbTi)B2 陶瓷都表现出比其组成元素的二元化合物更高的硬度 [33] 。高熵碳化物 (ZrTaNbTi)C 陶瓷用 20dpa 剂量的 3 MeV Zr 离子辐照后，仍能保持晶格完整，晶胞膨胀仅 0.2%，具有良好的抗辐照损伤特性 [34] 。然而高熵碳化物(HfZrTaNbTi)C 由于阳离子亚晶格扭 曲，增强了声子散射，导致其热导率低于其组元的二元碳化物 [35] 。 高熵带来的性能提升或下降与其引起的微纳结构变化有着十分密切的关系。 透射电子显 微镜(TEM)能够在纳米及原子尺度给出材料的结构、元素分布和价态信息，这有助于深刻理 解高熵固溶结构的形成机制以及结构与性能之间的内在关系。Zhang 等 [36] 利用 TEM 高分辨 像在三元合金 CrCoNi 中发现了短程有序结构，短程有序结构可以增大层错能并提高硬度。 Lei 等 [37] 利用球差校正透射电子显微镜 (ACTEM) 的环形明场像 (ABF) 在高熵合金 TiZrHfNb 中发现了含氧化合物构成的纳米短程序结构，改变了位错剪切模式，丰富了位错滑移体系， 增强了强度和延展性。Ding 等 [38] [41][42] 。这种浓度波动或者类似的原子分布不均匀的现象， 将减小按照均匀分布计算的混合...…”