Siao Li Liew, Nafisah Bte Mohd Rafiq, Xi Ping Ni, Anqi Sng, Poh Chong Lim, Jun Zhou, and Shijie Wang. Reinforced High-Entropy Fluorite Oxide Ceramic Composites for Thermal Barrier Coating Application.
Inorganic Chemistry 2025 64 (4), 1726-1733
DOI: 10.1021/acs.inorgchem.4c03942
Abstract:
High-entropy ceramics hold promise for application as thermal
barrier coating materials. However, a key challenge in practical applications lies in
the low fracture toughness compared to that of yttria-stabilized zirconia (YSZ).
Herein, we designed (Hf,Zr,Ce,M)O2−δ−Al2O3 (M = Y, Ca, and Gd) ceramic
composites by following a set of fundamental guidelines. First-principles
calculations predicted that the inclusion of Al2O3 in compositions containing
the other four binary oxides decreased the propensity for single high-entropy
phase formation. Instead, it increased the potential for Al2O3 to form a second
phase within the high-entropy ceramic matrix, compared to compositions without
Al2O3. Ceramic composites consisting of the Al2O3 second phase in a highentropy
fluorite oxide (Hf,Zr,Ce,M)O2−δ matrix were synthesized in situ via
conventional solid-state reactions from the five constituent binary oxides. Both
the hardness and fracture toughness of the ceramic composites were enhanced
due to toughening mechanisms from the discrete Al2O3 particles, microcracks,
and crack deflections. Additionally, the ceramic composites exhibited coefficients of thermal expansion and thermal conductivities
comparable with those of YSZ. Our findings demonstrated the potential of the high-entropy (Hf,Zr,Ce,M)O2−δ−Al2O3 ceramic
composites for advanced thermal barrier coating materials and offered a possible approach to reinforce other high-entropy oxidebased
ceramic systems.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the Agency for Science, Technology and Research (A*STAR) - Mat-GDT (Materials − Generative Design Testing) Framework
Grant Reference no. : OUNI241001aENTMTC
This research is supported by core funding from: Future Energy Acceleration & Translation (FEAT) Strategic Research & Translation Thrust (SRTT)
Grant Reference no. : NA