Rare‐earth (RE) silicates environmental barrier coatings (EBCs) are prone to accelerate failure resulted from molten calcium–magnesium–aluminum silicate (CMAS), which presents significant challenges to the design and development of durable EBCs. In this study, X1‐Gd2SiO5 and X2‐Er2SiO5 coatings were explored on their corrosion resistance to CMAS melts with different Ca/Si ratios (1.1, 0.75, 0.64, and 0.42) at 1350°C for 25 and 50 h, respectively. Results showed that with the Ca/Si ratio increasing, CMAS viscosity decreased and a more intense corrosion reaction with coatings occurred. Garnet phase was only observed in X2‐Er2SiO5 coating corroded by CMAS with high Ca/Si ratios, which could be beneficial for improving corrosion resistance. The X2‐Er2SiO5 phase, which is composed of [SO4] and [REO6]/[REO7] polyhedrons, exhibits better corrosion resistance due to its more stable crystal structure, lower reactivity with CMAS, and the radius difference between the RE ions and Ca2+.

中文翻译：

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硅酸钙镁铝成分对X1-Gd2SiO5和X2-Er2SiO5环境屏障涂层反应行为的影响

稀土（RE）硅酸盐环境屏障涂层（EBC）很容易因熔融硅酸钙镁铝（CMAS）而加速失效，这对耐用 EBC 的设计和开发提出了重大挑战。本研究中，X1-Gd2二氧化硅5和X2-Er2二氧化硅5研究了涂层对不同Ca/Si比（1.1、0.75、0.64和0.42）的CMAS熔体的耐腐蚀性，分别在1350℃下25小时和50小时。结果表明，随着Ca/Si比的增加，CMAS粘度降低，与涂层发生更强烈的腐蚀反应。仅在 X2-Er 中观察到石榴石相2二氧化硅5高Ca/Si比的CMAS腐蚀涂层，有利于提高耐腐蚀性能。 X2-Er2二氧化硅5相，其由 [SO4] 和 [REO6]/[REO7] 多面体，由于其更稳定的晶体结构、与 CMAS 的反应性较低以及 RE 离子和 Ca 之间的半径差异，表现出更好的耐腐蚀性2+。