Insight into the synergistic effect of rare-earth elements on the CMAS corrosion behavior in (RE1/4Tm1/4Yb1/4Lu1/4)2Si2O7 (RE = Gd, Ho and Sc) materials at 1300 °C

Rare-earth disilicates RE₂Si₂O₇ have been widely acknowledged as state-of-the-art environmental barrier coating material in commercial applications due to its superior thermochemical stability and high temperature water vapor corrosion resistance. However, a primary limitation of RE₂Si₂O₇ EBCs for high-performance aero-engine applications-particularly at sustained operating temperatures exceeding 1300 °C is their inadequate resistance to CMAS deposits. The advent of high-entropy or multicomponent design in materials engineering has brought new inspiration to address this bottleneck, and its effectiveness has been proven in recent research. In fact, all these benefits originate from the introduction of various rare-earth ions and their respective advantages in coupling. However, the correlation mechanism between the efficacy of rare-earth components and the final corrosion resistance is still unclear, and an exact guideline for component elements selection is still absent.

Recently, a joint team of Professor Sun Luchao’s group from Institute of Metal Research, Chinese Academy of Sciences, and Professor Wang Jingyang’s group from Liaoning Academy of Materials confirmed the possibility of achieving tunable CMAS corrosion resistance in rare-earth disilicates through the synergistic effect of multiple rare-earth components through three novel multicomponent rare-earth disilicate EBC materials, and provided a criterion for designing multicomponent rare-earth silicates with enhanced CMAS corrosion resistance.

This team published their work in Journal of Advanced Ceramics on June 2, 2026.

“The findings in this work provide valuable insights for in-depth understanding of the synergistic effects among rare-earth components and the correlation mechanism of multicomponent rare-earth disilicates.” Said Jingyang Wang, Vice President of Liaoning Academy of Materials (LAM) and the director of Institute of Coating Technology for Hydrogen Gas Turbines in LAM (China).

“In this study, three multicomponent (RE_1/4Tm_1/4Yb_1/4Lu_1/4)₂Si₂O₇ (RE = Gd, Ho and Sc) materials were designed and exposed to CMAS at 1300 °C for durations of 1, 4, and 50 h. Mechanistic analysis reveals that the performance divergence primarily stems from distinct corrosion mechanisms: (Gd_1/4Tm_1/4Yb_1/4Lu_1/4)₂Si₂O₇ and (Ho_1/4Tm_1/4Yb_1/4Lu_1/4)₂Si₂O₇ predominantly undergo dissolution-reprecipitation processes, whereas (Sc_1/4Tm_1/4Yb_1/4Lu_1/4)₂Si₂O₇ is dominated by intergranular corrosion penetration. Such mechanistic transition is attributable to compositional tuning of rare-earth elements (Gd and Ho to Sc) in the silicates.” Said Luchao Sun, a professor from Institute of Metal Research, Chinese Academy of Sciences (China).

“In this study, elements such as Gd and Ho were proven to reduce the Ca/Si ratios by accelerating the precipitation of apatite phase during reaction. This process not only diminishes calcium in CMAS to reduce its corrosion aggressiveness but also retards CMAS diffusion through the formation of a dense product layer, collectively enhancing the corrosion resistance of disilicates. Thus, an optimal stoichiometric ratio between active (e.g., Gd and Ho) and inert (e.g., Yb and Lu) elements is essential to synergistically activate the precipitation for corrosion mitigation and the intrinsic resistance enhancement, thereby maximizing CMAS corrosion resistance in disilicate systems.” Said Luchao Sun.

About Author

Luchao Sun is currently a professor of advanced ceramics and composites division, Institute of Metal Research, Chinese Academy of Sciences. 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.

Jingyang Wang is currently the Vice President of Liaoning Academy of Materials (LAM) and the director of Institute of Coating Technology for Hydrogen Gas Turbines in LAM. His research covers fundamental research and engineering applications of structural ceramics, composite materials and high-temperature protective coatings for extreme service environments. 

Ziyu Wang is currently a doctor candidate in Shenyang National Laboratory for Materials Science, Institute of Matel Research. His research focuses on the composition design, preparation, and performance optimization of the environmental barrier coatings for aero-engines.

Funding

This work was supported by the National Natural Science Foundation of China (U21A2063); LiaoNing Revitalization Talents Program (XLYC2203090); International Partnership Program of the Chinese Academy of Sciences (172GJHZ2022094FN).

DOI Link: https://doi.org/10.26599/JAC.2026.9221330

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 2024 IF is 16.6, ranking in Top 1 (1/34, Q1) among all journals in “Materials Science, Ceramics” category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508