Mechanism-Guided Design of High-Entropy Ceramic Architectures for Hydrogen and Fusion Energy Systems

About the project

About the Project The transition toward net-zero energy technologies requires materials capable of operating under increasingly aggressive environments. Hydrogen-fuelled gas turbines demand advanced Environmental Barrier Coatings (EBCs) for SiC/SiC ceramic matrix composites, where resistance to steam corrosion, calcium–magnesium–aluminosilicate (CMAS) attack and thermal cycling is essential. Concurrently, future fusion reactors employing Dual-Coolant Lead-Lithium (DCLL) breeder blankets require electrically insulating Flow Channel Inserts (FCIs) that can withstand liquid Pb-Li corrosion, severe thermal gradients and intense neutron irradiation. Rare-earth oxides have emerged as promising next-generation thermal and environmental barrier materials owing to their low thermal conductivity, excellent phase stability and CMAS resistance. More recently, high-entropy zirconates (HEZs) and high-entropy hafnates (HEHs) have demonstrated superior defect engineering capability, enhanced radiation tolerance and reduced thermal conductivity arising from severe lattice distortion. However, their application has been largely confined to turbine coatings, while their potential for fusion blanket ceramic architectures remains almost unexplored. This project aims to bridge aerospace and fusion materials science by developing compositionally complex ceramic systems capable of serving both as EBC top-coat materials and as candidate ceramic architectures for fusion Flow Channel Inserts. Aim To develop high-entropy zirconate and hafnate ceramic architectures possessing superior thermo-chemical stability, corrosion resistance and irradiation tolerance for applications in hydrogen-fuelled turbine EBCs and fusion blanket FCIs. Objectives Design compositionally complex zirconate and hafnate systems using CALPHAD and thermodynamic modelling. Synthesise high-entropy pyrochlore and defect-fluorite ceramics through solid-state sintering routes. Characterise phase stability, thermal conductivity, thermal expansion and mechanical properties. Evaluate degradation mechanisms under representative hydrogen turbine environments, including high-temperature steam and CMAS attack. Investigate corrosion behaviour in liquid Pb-Li and assess electrical insulation characteristics relevant to fusion FCIs. Study irradiation tolerance using ion irradiation as a surrogate for neutron damage. Develop hybrid SiC–high-entropy ceramic architectures for multifunctional coating and insert applications. Methodology Computational materials design will be employed to identify compositionally stable rare-earth zirconate and hafnate systems. CALPHAD calculations and defect chemistry modelling will be integrated with physics-informed machine learning to establish composition–structure–property relationships. Selected compositions will be synthesised and characterised using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Thermophysical properties including thermal conductivity and thermal expansion coefficients will be measured using laser flash analysis and dilatometry. Environmental durability will be evaluated through steam corrosion and CMAS infiltration experiments relevant to hydrogen combustion turbines. Liquid Pb-Li exposure tests will be conducted to investigate dissolution kinetics and interfacial reactions associated with fusion blanket environments. Ion irradiation experiments will provide insights into defect accumulation and phase stability under radiation damage. Hybrid ceramic architectures combining SiC substrates with high-entropy ceramic layers will also be explored to enhance fracture resistance while retaining corrosion and irradiation resistance. Expected Outcomes The project is expected to deliver: Novel high-entropy zirconate and hafnate compositions with exceptional high-temperature stability. Fundamental understanding of entropy-driven corrosion and irradiation resistance. Mechanistic insights linking defect chemistry to degradation behaviour. Prototype multifunctional ceramic architectures suitable for both hydrogen turbine EBCs and fusion blanket FCIs. High-impact publications Significance This research establishes a new interdisciplinary platform connecting aerospace propulsion and fusion energy technologies. The outcomes will contribute to the development of durable ceramic systems for sustainable aviation and future fusion reactors, supporting global decarbonisation and advanced energy strategies.

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