ZrB₂-20SiC (ZS20) composite and its derivatives doped with 5 vol% Sc₂O₃, Y₂O₃, and La₂O₃ were densified using hot press sintering to investigate the influence of rare earth oxides on their high temperature oxidation and ablation behavior. Isothermal oxidation testing at 1773 K indicate that rare earth oxides modification lowers activation energy and slightly accelerates weight gain during the initial phase. As oxidation progresses, the weight gain of ZS20 increases sharply. The sample doped with La₂O₃ (ZS20L5) exhibits the lowest oxidation weight gain, with a porosity of only 1.8 % after oxidation. Cyclic ablation tests at the middle-low temperature zones indicate that ZS20L5 exhibits the lowest linear and mass ablation rates. Thermodynamic analyses demonstrate that La₂O₃ preferentially reacts with SiO₂ to form La₂Si₂O₇, which demonstrates a more effective oxygen barrier property compared to ZrSiO₄. Additionally, La₂O₃ enhances the fluidity of the glass phase, effectively filling cracks, sealing pores, and blocking the penetration of oxygen.

The advancement of cutting-edge technologies, including hypersonic vehicles, aerospace transportation platforms, and fusion energy systems, is driving the transition in electromagnetic stealth requirements from room-temperature conditions to extreme environments. However, traditional wave-absorbing materials suffer severe performance degradation at temperatures above 500 °C or under corrosive and irradiated conditions. Owing to their unique thermodynamic stability and tunable multi-element structures, high-entropy materials provide a promising route to address these challenges. This review systematically summarizes the electromagnetic-wave absorption behavior and structural evolution of high-entropy alloys, high-entropy ceramics, and high-entropy MAX/MXene materials under extreme conditions such as oxidation (550-1600 °C), salt-spray exposure, cryogenic temperatures, and thermal shock. Particular emphasis is placed on elucidating the mechanisms enabling efficient electromagnetic dissipation, including composition design, microstructural engineering, and multi-mode coupling. Reported studies indicate that these materials can achieve reflection losses below −30 dB and effective bandwidths exceeding 10 GHz across a variety of systems while maintaining excellent environmental stability. Future research opportunities include machine-learning-assisted multi-objective optimization, scalable fabrication strategies, and the development of sustainable high-entropy absorber systems for practical deployment in extreme environments.

Thermal protection coatings for aerospace applications require robust mechanical properties, exceptional thermal insulation, and high impact resistance to safeguard critical hot-section components and thereby extend their service life. Previous studies have confirmed that high-entropy titanate (La_0.3K_0.1Ca_0.2Sr_0.2Ba_0.2)TiO_3+δ (HE-LKTO) materials have excellent thermal protection properties and mechanical properties. To evaluate the viability of the HE-LKTO for Thermal protection coatings, a novel high-entropy titanate coating with a non-equimolar A-site composition was fabricated via atmospheric plasma spraying. The as-sprayed coatings subsequently underwent a comprehensive analysis of their microstructure and phase structure. Guided by the experimental results, the coating prepared under the optimized conditions was systematically investigated for its thermal protection performance via plasma flame thermal shock testing. The failure mechanism was revealed by analyzing the coating’s dynamic behavior under extreme heat flux. Results show that the HE-LKTO coating prepared at 36 kW exhibits the optimal microstructure: the sprayed particles achieve complete melting and effective spreading, resulting in the lowest surface roughness and porosity. In addition, HE-LKTO coating maintains structural integrity at ablation temperatures of 1400 ℃, exhibiting excellent high-temperature protection performance. At the extreme temperature of 1600 ℃, however, the coating began to spall as a result of accumulated thermal stress induced by the mismatched thermal expansion coefficients between the coating and substrate, as well as crack propagation along interlamellar boundaries and interface separation. This work not only validates the great potential of HE-LKTO as thermal protection coatings but also provides crucial insights into its failure mechanism, laying a foundation for future performance enhancement.

With the growing prominence of electromagnetic pollution, the development of lightweight, flexible, and highly efficient electromagnetic wave (EMW) absorption materials has become an important research focus. Inspired by biological Turing structures, this study successfully prepares novel flexible ZrO₂/C nanofibers with a spotted reaction-diffusion pattern via a controlled oxidation strategy from preformed ZrC/C nanofibers. The ZrO₂/C nanofibers sample contains ZrO₂ particles embedded within a carbon matrix, which contributes to the formation of numerous heterogeneous interfaces. Furthermore, both the ZrO₂ and carbon matrix exhibit a mixed amorphous-nanocrystalline structure, thereby enhancing interfacial diversity and density. The ZrO₂/C Turing structural characteristic enhances impedance matching in the nanofibers and significantly improves the polarization loss capability. The obtained novel nanofibers achieve a minimum reflection loss of −59.20 dB, a maximum effective absorption bandwidth of 5.84 GHz, and require a matching thickness of only 2.39 mm. Computer simulation technology (CST) simulations indicate a maximum radar cross-section reduction of 34.94 dB m², highlighting the material’ s radar stealth capability. The study provides a new strategy for designing lightweight and high-performance fiber-based EMW absorption materials.

Al₂O₃-based directionally solidified eutectic (DSE) ceramics are recognized as promising candidates for high-temperature structural materials in advanced aeroengines. Nevertheless, their corrosion resistance at elevated temperatures continues to pose a critical challenge, limiting broader application in hot-section components. This study investigates corrosion behavior of RE₃Al₅O₁₂ (REAG)/Al₂O₃ (RE = rare earth) DSE ceramics in water vapor atmosphere (90 H₂O(g) + 10 vol% air(g)) at 1500°C for durations up to 200 h, with focus on the influence of eutectic structure and RE elements in garnet phases via examining three samples (high-entropy (Y_0.2Gd_0.2Ho_0.2Er_0.2Yb_0.2)₃Al₅O₁₂ DSEs fabricated at 10 and 300 mm/h and YAG/Al₂O₃ DSE grown at 10 mm/h). The results indicate that REAG/Al₂O₃ DSE ceramics exhibit excellent water vapor corrosion resistance at 1500°C for up to 200 h, with mass loss values ranging from −0.00757 to −0.00708 mg·cm⁻²·mg⁻¹. During corrosion, Al₂O₃ phase acts as corrosion-susceptible component compared to REAG phase, with corrosion depth showing a nearly linear relationship with the average Al₂O₃ lamellar width. In addition, garnet phases experience slight grain growth, reducing the contact area between water vapor and Al₂O₃ phase; Gd demonstrates the slowest diffusion rate when compared to other RE elements. Despite these changes, all samples maintain their preferred crystallographic orientations, confirming the structural stability of REAG/Al₂O₃ DSEs under water vapor atmosphere at 1500°C.