Corrosion performance of high-entropy (Ho0.2Er0.2Tm0.2Yb0.2Lu0.2) 2Si2O7 environmental barrier coating material under CMAS conditions at 1500 ℃

Zhenya Zhang; Shuai Yuan; Zihao Zhu; Wei Gao; Yifan Meng; Zhaolu Xue; Tengfei Xiang; Yizhou Shen; Kai Yan; Gobinda Gyawali; Shihong Zhang

doi:10.1016/j.exm.2026.01.001

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Extreme Materials ›› 2026, Vol. 2 ›› Issue (2) : 100018. DOI: 10.1016/j.exm.2026.01.001

Corrosion performance of high-entropy (Ho_0.2Er_0.2Tm_0.2Yb_0.2Lu_0.2) ₂Si₂O₇ environmental barrier coating material under CMAS conditions at 1500 ℃

Zhenya Zhang ^a ,
Shuai Yuan ^a ,
Zihao Zhu ^a ,
Wei Gao ^a ,
Yifan Meng ^a ,
Zhaolu Xue ^a ,
Tengfei Xiang ^a ,
Yizhou Shen ^b ,
Kai Yan ^c ,
Gobinda Gyawali ^a ,
Shihong Zhang ^a^,⁺

Author information +

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Abstract

Improving the corrosion resistance of environmental barrier coatings (EBCs) to molten calcium-magnesium-aluminosilicate (CMAS) salt is an urgent requirement for aeroengine blades. In this work, a novel high-entropy (Ho_0.2Er_0.2Tm_0.2Yb_0.2Lu_0.2)₂Si₂O₇ ((5RE_0.2)₂Si₂O₇) environmental barrier coating material was developed, and molten CMAS corrosion resistance of (5RE_0.2)₂Si₂O₇) was systematically investigated at 1500 °C. The prepared (5RE_0.2)₂Si₂O₇ ceramic possesses a single and stable β-phase structure with high-temperature stability from room temperature to 1500 ℃. The thermal conductivity of (5RE_0.2)₂Si₂O₇ ranges from 1.46 to 3.49 W·m⁻¹·K^-1 at room temperature to 1500 ℃. A rapid reaction of (5RE_0.2)₂Si₂O₇ with molten CMAS produced Ca₂RE₈(SiO₄)₆O₂ apatite at 1500 ℃. The reaction layer thickness was only 95.9±8.6 μm which effectively inhibited the infiltration and diffusion of molten CMAS salt. In contrast, Yb₂Si₂O₇ ceramic, when exposed to molten CMAS at 1500 ℃, showed no reaction. Instead, the molten CMAS salt penetrated into the interior of Yb₂Si₂O₇ along grain boundaries and voids, forming bubble cracking and ultimately, structural degradation. These results suggest that the high-entropy (5RE_0.2)₂Si₂O₇ ceramic material is a potential candidate for next-generation EBC with excellent resistance to CMAS corrosion.

Key words

Environmental barrier coatings / high-entropy / thermal conductivity / Ca₂RE₈(SiO₄)₆O₂ apatite / infiltration

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Zhenya Zhang , Shuai Yuan , Zihao Zhu , et al . Corrosion performance of high-entropy (Ho_0.2Er_0.2Tm_0.2Yb_0.2Lu_0.2) ₂Si₂O₇ environmental barrier coating material under CMAS conditions at 1500 ℃[J]. Extreme Materials. 2026, 2(2): 100018 https://doi.org/10.1016/j.exm.2026.01.001

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Acknowledgments

This work was supported by Anhui Provincial Natural Science Foundation (2408085JX008), China Postdoctoral Science Foundation (2024T170003), Anhui Provincial Natural Science Foundation (2308085QE135), Construction of International Surface Technology Standards for New Energy Vehicles and Integrated Circuit Industry (2023MKS01).