Efficient design and experimental verification of Gd2Zr2O7-based thermal barrier coating materials based on first-principles calculations

TBCs are widely applied to engine turbine blades to extend the service life and improve engine thrust-to-weight ratio and efficiency. The rapid advancement of aircraft engines has placed higher demands on the performance of TBCs. GZO is a next-generation TBC material. Rare earth element doping can further optimize the comprehensive performance of GZO, thereby improving its application adaptability and service durability in advanced aero-engines.

In most existing studies on rare-earth doped GZO, it is generally believed that rare-earth dopants form substitution-type solid solutions by replacing Gd. However, as the radius of the rare-earth decreases, their tendency to occupy interstitial sites in the GZO lattice increases; this change in solid solution mechanism may lead to unexpected improvements in the performance of GZO. Additionally, traditional experimental methods primarily rely on repeated trials, trial-and-error, and testing to indirectly infer the solid-solution mechanisms of dopants. This approach is not only inefficient but also costly. First-principles calculations based on density functional theory (DFT) can reveal the electronic structure, lattice dynamics, and heat transport mechanisms of materials at the atomic scale, making them particularly suitable for rapid screening and mechanism analysis of multi-component doping systems. Analyzing the solid-solution mechanisms of dopant elements through calculating defect formation energies can clearly elucidate the mechanisms by which doping affects material properties, saving significant time and experimental costs compared to experimental methods.

Recently, a team led by Professor Lei Guo at Tianjin University employed first-principles calculations to investigate doping modification strategies for GZO TBC materials. They revealed the solid-solution mechanism of the dopant elements and obtained 11.76 at.% Yb and 5.88 at.% Sc co-doped GZO (GYbSc) material. It exhibits extremely low thermal conductivity, high thermal expansion coefficient, and excellent toughness.

This study provides an efficient design method for developing novel ultra-high-temperature, highly insulating, and corrosion-resistant TBC materials. GYbSc material developed in this study meets the performance requirements for thermal barrier coatings in next-generation aircraft engines and gas turbines.

The team published their work in Journal of Advanced Ceramics on April 9, 2026.

“We employed first-principles calculations to investigate the solid-solution mechanism of Yb and Sc in GZO, elucidated the mechanisms by which different doping methods affect the properties of GZO, and obtained 11.76% Yb and 5.88% Sc co-doped GZO (GYbSc) material. We synthesized GYbSc using the chemical coprecipitation method and tested its properties. Experimental results indicate that GYbSc exhibits excellent mechanical and thermophysical properties. The combination of first-principles calculations and experiments can accelerate the rapid development of TBC materials.” said Lei Guo, a professor at the School of Materials Science and Engineering at Tianjin University and an expert specializing in thermal barrier coating materials.

“First-principles calculations investigating the solid-solution mechanism use defect formation energy as a criterion. The results indicate that during Yb doping, Yb substitutes for Gd to enter the GZO lattice; during co-doping of Yb and Sc, when the Sc content is ≤5.88 at.%, Sc enters the interstitial sites of the GZO lattice, and as the doping concentration continues to increase, Sc begins to substitute for Gd. Additionally, first-principles calculations reveal the influence of Yb and Sc single and co-doping on the mechanical and thermophysical properties of GZO. The optimized GYbSc material exhibits extremely low thermal conductivity, high coefficient of thermal expansion, and excellent toughness,” said Lei Guo.

“GYbSc has a hardness of 12.76 GPa and a toughness of 2.09 MPa·m^1/2; its coefficient of thermal expansion at 1300 °C reaches 11.059 × 10^-6 K^-1; its thermal conductivity at 1200 °C is as low as 0.935 W·m^-1·K^-1; and exhibits greater CMAS corrosion resistance than GZO,” said Lei Guo.

Other contributors include Kun Wang from the School of Materials Science and Engineering at Tianjin University in Tianjin, China; Xiaohu Yuan, Wei Wang, and Xiufang Gong from the State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment

About Author

Lei Guo is a Professor and Ph.D. supervisor at the School of Materials Science and Engineering, Tianjin University, China, and Deputy Director of the Institute of Welding and Advanced Manufacturing Technology. His research focuses on high-temperature protective coatings for advanced engines, hydrogen-resistant coatings and AI for materials. He has published over 100 SCI-indexed papers with an H-index of 41 and holds five authorized national invention patents; Over the past five years, he has secured three National Natural Science Foundation of China General Projects and one Ye Qisun Key Fund grant. He received the First Prize in the Science and Technology Award from the Chinese Society for Corrosion and Protection (ranked 1st). He has been honored with the title of “Outstanding Young Scientific and Technological Talent of Tianjin,” named one of Tianjin University’s “Top Ten Favorite Mentors,” and received the “Jun porcelain Award” for advanced ceramics, among other accolades.

Funding

This research is sponsored by the Innovation Project (D9625BCD), and the National Natural Science Foundation of China (Grant Nos. 52471087 and U2541255).

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