With the advances in thrust-weight ratio, the service temperature of gas turbine engines even exceeds 1500℃, which is urgent to develop high/superhigh temperature thermal protection systems for long-term service. Niobium alloys are increasingly viewed as a promising structural material for high-temperature applications due to their superior high-temperature mechanical strength, but the “pest” catastrophic oxidation greatly restricts its further application. Herein, a HfC-HfO₂ modified silicide coating was prepared via an innovative method of halide-activated pack cementation combined with liquid-plasma-assisted particle deposition and sintering on niobium alloys, endowing the composite coating with excellent hot corrosion resistance and high-temperature oxidation resistance. This modified multilayer coating is characterized by the synergistic combination of a dense NbSi₂ inner layer and a HfC-HfO₂ porous outer layer, exhibiting a significant improvement in high-temperature performance compared with the single NbSi₂ coating. The corroded gain of composite coating is only 13.94 mg·cm^-2 after the corrosion time of 200 h at 900℃, and shows an intact oxide scale surface after oxidation at 1500℃ for 500 min. This improvement is ascribed to the formed robust Hf-rich skeleton provided by the deposited HfC-HfO₂ layer, which can accelerate the formation of the high stability corroded layer/oxide scale. Besides, multiple stress release mechanisms of the composite coating at high temperatures also provide huge contributions for long-term service. All these merits render the HfC-HfO₂ modified composite coating on niobium alloys competitive for the development of high/superhigh temperature thermal protection systems for long-term service.

The escalating energy crisis and the demand for thermal protection under extreme environments require materials that effectively suppress heat transport while maintaining long‐term thermal stability. However, thermal insulation ceramics inherently suffer from the dual challenge of simultaneously inhibiting lattice heat transfer and radiative heat transfer. Here, we establish a synergistic regulation of solid‐state and radiative heat transfer through rare‐earth site compositional screening and entropy engineering. This principle informs the development of a physics‐informed constrained random forest model for predicting wavelength‐dependent infrared radiation properties in the RE ₃ TaO ₇ system, facilitating efficient screening of candidate compositions. High‐throughput screening of 504 structural variants has led to the identification of 21 candidates with a representative high‐entropy ceramic of (Nd _0.2 Sm _0.2 Gd _0.2 Dy _0.2 Y _0.2 ) ₃ TaO ₇ that exhibits ultralow near‐infrared transmittance (< 1% over 0.78–2.5 µm), high broadband emissivity (> 0.9 over 2.5–14 µm) and low radiative thermal conductivity of 0.035 W m ⁻¹ K ⁻¹ at 1273 K. This work makes progress in high‐entropy thermal‐protective ceramics for extreme environments and establishes a general framework for advanced thermal insulation materials.

To enhance the ablation resistance of TiAl alloy, a HfSi2 nanocomposite coating was in-situ formed on the surface of TiAl alloy using a one-step liquid plasma-assisted particle deposition and sintering (LPDS) method. As a comparison, the ceramic coating was prepared using the plasma electrolytic oxidation (PEO) technique. The surface and cross-section morphologies, the chemical composition, and the phase identification of two coatings are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructure evolution and ablation resistance of TiAl alloy, PEO ceramic coating, and HfSi2 nanocomposite coating under flame (>1500°C) ablation for different durations (90,180, and 360 s) is investigated, respectively. Results indicate that the HfSi2 particles can be incorporated into the coating and partially oxidized to form HfO2 during the LPDS process. In addition, the PEO ceramic coating surface exhibited approximately 15.4% peeling areas, whereas no peeling was observed in the HfSi2 nanocomposite coating. Such excellent high-temperature ablation resistance of the nanocomposite coating is mainly ascribed to the HfO2 phase acting as a framework for anchoring the HfO2-SiO2 oxide layer formed during the ablation of HfSi2 oxide effectively hindering crack propagation and oxygen diffusion. Hence, the LPDS technique presents a prominent pathway to designing and fabricating multifunctional ceramic coatings that incorporate various functional particles, thereby enhancing the thermal protection of alloy substrates.