Ceramic matrix composites, represented by SiCf/SiC, are preferred high-temperature structural materials for aircraft engines components due to their high-temperature stability, low density, and excellent high-temperature mechanical properties. When exposed to harsh combustion environments, the environmental barrier coatings (EBCs) are required to be developed on the surfaces of these components with the objective of providing protection against corrosive media and extending the lifespan of the aircraft engines. In recent years, the exploration of innovative materials that exhibit significant resistance against calcium-magnesium-aluminum-silicates (CMAS) at temperatures exceeding 1300 °C has emerged as a pivotal task in the development of EBCs. However, for the mostly material systems applied as EBC at 1500 ℃, the CMAS will penetrate the whole coating along their grain boundaries, ultimately resulting in the coating failure.
Recently, a team of material scientists led by Jingyang Wang from Institute of Matel Research innovatively induced the Y4Al2O9/Y2O3 composite applied as EBCs to accelerate the consumption of CMAS and enhance the CMAS resistance during the reaction. This composite not only improves the formation of CMAS crystallization products but also rapidly consumes the CMAS glass with minimal consumption of the coating material to generate reaction products at 1300 ℃ and 1500 ℃. This process effectively solidifies CMAS, preventing its infiltration through grain boundaries. Y4Al2O9/Y2O3 exhibits excellent CMAS resistance, and can be considered as a potential EBCs material used at higher temperature in next-generation gas turbine.
The team published their work in Journal of Advanced Ceramics on May 29, 2025.
"In this study, a novel Y4Al2O9/Y2O3 ceramic was designed and prepared using the hot-pressing method, and the interactions of as-sintered Y4Al2O9/Y2O3 composite with CMAS at 1300 °C and 1500 °C were investigated in detail. After corrosion at different durations, phase compositions, morphologies and the thicknesses of the reaction layers between the molten CMAS and the Y4Al2O9/Y2O3 composite were characterized. The chemo-thermal mechanisms underlying these interactions between the Y4Al2O9/Y2O3 ceramic and CMAS were discussed based on the above results." said Jiangyang Wang, professor at Shenyang National Laboratory for Materials Science at Institute of Metal Research (China).
The YAM/Y2O3 composite investigated in this work exhibits significant CMAS resistance at both 1300 ℃ and 1500 ℃, with no significant grain-boundary penetration by CMAS glass. The rapid formation of dense product layers reduces the infiltration of CMAS into the substrate along the grain boundaries and reaction rate. The analysis of the reaction mechanism demonstrates that the incorporation of Al3+ and Y3+ into the composition promotes the formation of garnet and cuspidine phases, which are enriched in higher silica and alkaline earth content (CaO and MgO). Moreover, the formation of garnet and cuspidine necessitates the consumption of 10.93 moles and 5.75 moles of CMAS, respectively, for every mole of YAM/Y2O3. Consequently, this significantly reduces the reactivity of CMAS and the consumption of EBC materials.
This study confirms the feasibility of selecting high-reactivity materials with CMAS at elevated temperatures in the chemical composition during material design, enabling rapid crystallization phase precipitation and effective CMAS melt consumption and may provide valuable insights to guide the design and development of excellent CMAS-resistant materials.
This work is financially supported the National Key R&D Program of China (2024YFB3714503); National Natural Science Foundation of China (52130204, U21A2063); LiaoNing Revitalization Talents Program (XLYC2203090); International Partnership Program of the Chinese Academy of Sciences (172GJHZ2022094FN).
About Author
Jingyang Wang is the Vice President of Liaoning Academy of Materials (LAM) and the director of Institute of Coating Technology for Hydrogen Gas Turbines in LAM. He is also a professor of Advanced Ceramics and Composites Division, Institute of Metal Research, Chinese Academy of Sciences (CAS). His research interests are focused on fundamental exploration and technological developments of structure ceramics, ceramic-matrix-composites, and high temperature thermal barrier coating and environmental barrier coating for extreme environmental applications.
Luchao Sun is currently a professor of advanced ceramics and composites division, Institute of Metal Research, Chinese Academy of Sciences. He received his PhD. degree in Materials Science from the University of Chinese Academy of Sciences in 2013. His main research interests cover theoretical and experimental investigations on advanced ceramics and composites for harsh environment applications and advanced materials for thermal/environmental barrier coatings.
Jie Li is a doctor candidate in Shenyang National Laboratory for Materials Science, Institute of Matel Research. Her research focuses on developing environmental coating materials applied at extreme high-temperature environment.
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2023 IF is 18.6, ranking in Top 1 (1/31, Q1) among all journals in "Materials Science, Ceramics" category, and its 2023 CiteScore is 21.0 (top 5%) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
