Design of multiple rare-earth (RE) principal elements is a practical strategy to optimize key property of RE disilicate environmental barrier coating (EBC). However, multi-RE component in the feedstocks may also introduce critical fabrication problems due to the different evaporating and crystallizing behaviors of the EBC containing various RE composition. We herein report the preparation of a novel multi-RE disilicate (Gd_1/6Tb_1/6Dy_1/6Tm_1/6Yb_1/6Lu_1/6)₂Si₂O₇ EBC by atmospheric plasma spraying (APS). The crystallization behavior of the as-deposited coating annealed at 1100°C–1300°C with different durations (5 and 20 h) in air and argon atmospheres were investigated through comprehensive characterization techniques. RE disilicate, RE mono-silicate, and RE apatite were detected in the as-sprayed coatings, and mono-silicate and apatite transform to RE₂Si₂O₇ with the increment of temperature and extension of annealing duration. Furthermore, the contribution of multiple RE to the formation of apatite phase is discussed. The results provide a fundamental understanding and may guide the controllable preparation of multi-RE disilicate EBC via APS method.

中文翻译：

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新型(Gd1/6Tb1/6Dy1/6Tm1/6Yb1/6Lu1/6)2Si2O7环境阻隔涂层的结晶和相演化

多种稀土 (RE) 主要元素的设计是优化稀土二硅酸盐环境屏障涂层 (EBC) 关键性能的实用策略。然而，由于含有各种稀土成分的 EBC 的不同蒸发和结晶行为，原料中的多稀土成分也可能引入关键的制造问题。我们在此报告了一种新型多稀土二硅酸盐 (Gd _1/6 Tb _1/6 Dy _1/6 Tm _1/6 Yb _1/6 Lu _1/6 ) ₂ Si ₂ O _7的制备EBC 通过大气等离子喷涂 (APS)。通过综合表征技术研究了在 1100°C–1300°C 下在空气和氩气氛中以不同持续时间（5 和 20 小时）退火的沉积涂层的结晶行为。在喷涂层中检测到稀土二硅酸盐、稀土单硅酸盐和稀土磷灰石，随着温度的升高和退火时间的延长，单硅酸盐和磷灰石转变为稀土₂ Si ₂ O _{7 。}此外，还讨论了多种稀土对磷灰石相形成的贡献。结果提供了一个基本的理解，并可能指导通过 APS 方法可控地制备多稀土二硅酸盐 EBC。