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Ceramic aerogels are attractive for their promising applications in thermal insulation, ultrafiltration, catalysis, and many other areas, owing to their high porosity, low density, high specific surface area, low thermal conductivity, and thermal stability. However, the practical applications of conventional ceramic aerogels are usually impeded by brittleness. Resilient ceramic aerogels overcame the brittleness of conventional ceramic aerogels and realized reversible compressibility, but they usually show brittleness under tensile stress and limited load‐bearing ability. In this short review paper, we reviewed the strategies to modify the mechanical properties of resilient ceramic aerogel. These strategies were achieved through tuning the deformation and moving ability of the nanowire building blocks and the deformation resistance provided by the aerogel architecture. Perspectives for further modifying the mechanical properties of resilient ceramic aerogel are also discussed. [ABSTRACT FROM AUTHOR]

SiC nanowires (SiC NWs) possess both high thermal stability of SiC ceramic and one‐dimensional nanoscale features, which makes them highly attractive as reinforcements in ceramics or building units in resilient ceramic nanowires aerogels (NWAs) as well as blocks for electronic nanodevices. Understanding the oxidation behavior of SiC NWs at high temperatures is essential for their practical applications. Herein, we investigated the oxidation behavior of SiC NWs at 900–1200°C in air. Two oxidation stages were found, including an initial stage controlled by the reaction between oxygen and SiC at the SiO2/SiC interface and a subsequent oxygen diffusion–dependent stage. The oxide scale thickness was strongly influenced by the radius of the SiC NWs. With the increase of the NW radius from 40 to 120 nm, the oxidation activation energy of the oxidation process increases from 84.05 to 98.32 kJ/mol. The thermal insulation performances of SiC NWA, which is composed of SiC NWs, have been improved after oxidation. The evolution of the thermal insulation performance of SiC NWA during oxidation is consistent with the trends of the growth of the amorphous oxide layer, which indicates that exploring the oxidation kinetics is of great significance in understanding the high‐temperature behavior of SiC NW‐based materials. The present work provides insight into exploring the size effects on oxidation of SiC NWs, which may be helpful to further understanding the high‐temperature applications of SiC NWA. [ABSTRACT FROM AUTHOR]

Pursuing novel thermal barrier–coating materials with lower thermal conductivity and high‐temperature stability can simultaneously improve the working efficiency and service temperature of a gas turbine. In this study, a series of high‐entropy RE2(Y0.2Yb0.2Nb0.2Ta0.2Ce0.2)2O7 (RE = La, Nd, Sm, Gd, Dy, and Er) oxides were prepared though solid‐state reaction. Through tuning the rare‐earth cations, an order–disorder transition occurs from certain partially ordered weberite structure (C2221) to disordered defective fluorite structure (Fm3¯$\bar{3}$m). All the high‐entropy RE2(Y0.2Yb0.2Nb0.2Ta0.2Ce0.2)2O7 oxides possess low thermal conductivity in the range of 0.91–1.34 W m−1 K−1 at room temperature, which can be attributed to increased lattice anharmonicity and disorder, resulting in additional phonon scattering. Herein, we proved that the incorporation of heterovalent cations at B‐sites in high‐entropy A2B2O7 crystals is an effective strategy to reduce the thermal conductivity without compromising the decrease of oxygen vacancy. Moreover, the high‐entropy RE2(Y0.2Yb0.2Nb0.2Ta0.2Ce0.2)2O7 oxides show the relatively higher thermal expansion coefficients of 10.3–10.7 × 10−6°C−1 and excellent phase stability at elevated temperatures. [ABSTRACT FROM AUTHOR]

Light, strong, and elastic ceramics are of great interest for widespread engineering applications but it is always been a challenge to design and fabricate such materials for the conflict that lightweight structure usually requires high porosity while high porosity often leads to low strength. Here, we report a lightweight (90.9% porosity) and ultra‐strong SiC nanowires network (SiC NN) constructed by highly inter‐bonded nanowires in a layered distribution through a facile way. The resulting lamellar SiC NN (L‐SiC NN) exhibits a nearly complete compressive resilience from 20% strain while showing significantly high compressive stress (5.7 MPa). In particular, the L‐SiC NN shows high storage modulus (12.3 MPa), small damping ratio (0.046), frequency invariant from 20 to 100 Hz, and fatigue resistance up to 100 000 compression‐release cycles. In addition, the L‐SiC NN possesses high‐temperature stability up to 1100°C in air and low thermal conductivity of 0.121 W m‐1 k‐1. These integrated features make the L‐SiC NN an attractive substitute for thermal insulators and mechanical energy storage in a harsh environment. [ABSTRACT FROM AUTHOR]

Thermal barrier coating materials with proper thermal expansion coefficient (TEC), low thermal conductivity, and good high‐temperature stability are of great significance for their applications in next‐generation turbine engines. Herein, we report a new class of high‐entropy (La0.2Sm0.2Er0.2Yb0.2Y0.2)2CexO3+2x with different Ce4+ contents synthesized by a solid‐state reaction method. They exhibit different crystal structures at different Ce4+ content, including a bixbyite single phase without Ce4+ doping (x = 0), bixbyite‐fluorite dual‐phase in the RE2O3‐rich region (0 < x < 2), and fluorite single phase in the stoichiometric (x = 2) and CeO2‐rich region (x > 2). The high‐entropy (La0.2Sm0.2Er0.2Yb0.2Y0.2)2CexO3+2x exhibit tailorable TECs at a large range of 9.04 × 10–6–13.12 × 10–6 °C–1 and engineered low thermal conductivity of 1.79–2.63 W·m–1·K–1. They also possess good sintering resistance and high‐temperature phase stability. These results reveal that the high‐entropy (La0.2Sm0.2Er0.2Yb0.2Y0.2)2CexO3+2x are promising candidates for thermal barrier coating materials as well as thermally insulating materials and refractories. [ABSTRACT FROM AUTHOR]

Here we prepared porous silicon oxynitride (Si2N2O) ceramics by reaction sintering of SiO2 and Si3N4 using five different rare‐earth oxides (RE2O3, RE = Lu, Yb, Y, Sm, and La) as sintering aids. The influences of RE2O3 on the formation, densification, microstructure, and mechanical properties of Si2N2O ceramics have been investigated in detail. The results have indicated that with the increase in RE ionic radius, the formation temperature of Si2N2O decreases, and the densification process could be promoted by RE2O3 with larger RE3+ ionic radius. In addition, microstructures and mechanical properties are highly dependent on the RE2O3 additives. With the increase in RE3+ ionic radius, Si2N2O changes from platelike crystals to elongated crystals. The samples doped with La2O3 and Sm2O3 with elongated crystals exhibit higher flexural strength and higher Vickers hardness. [ABSTRACT FROM AUTHOR]

Pressureless sintering of pure γ-Y2Si2O7 powders that had been synthesized by a solid-liquid reaction method using Y2O3 and SiO2 powders with Li2O, MgO, and Al2O3 additives was reported. The sintering kinetics of γ-Y2Si2O7 powders was analyzed to track details of densification evolution. Apparent activation energies of the densification of γ-Y2Si2O7 powders were reported for the first time, which was 57.1, 96.6, and 100.2 kJ/mol for the powders with Li2O, MgO, and Al2O3 additives, respectively, indicating that Li2O could promote the densification behavior effectively. The flexural strengths as a function of temperature for the γ-Y2Si2O7 ceramics with different additives were also investigated. The degradation of high-temperature flexural strength was mainly ascribed to the softening of grain-boundary glassy phase. γ-Y2Si2O7 specimens fabricated using the powders with MgO or Al2O3 additives exhibited better high-temperature mechanical properties. [ABSTRACT FROM AUTHOR]

Porous β- Si3 N4 ceramics are sintered at 1600°C in N2 and postheat treated at 1500°C under vacuum using Li2 O and Y2 O3 as the sintering additives. The partial sintering and phase transformation are promoted at low temperature by the addition of Li2 O. The addition of Y2 O3 is advantageous for the formation of high aspect ratio β- Si3 N4 grains. After postheat treatment, a large amount of intergranular glassy phase is removed, and the Li content in the samples is decreased. By this method, the β- Si3 N4 porous ceramic with a porosity of 54.1% and high flexural strength of 110 ± 8.1 MPa can be prepared with a small amount of sintering additives, 0.66 wt% Li2 O and 0.33 wt% Y2 O3, and it is suitable for high-temperature applications. [ABSTRACT FROM AUTHOR]

Porous β- Si3 N4 ceramics are sintered at 1600°C in N2 and postheat treated at 1500°C under vacuum using Li2 O and Y2 O3 as the sintering additives. The partial sintering and phase transformation are promoted at low temperature by the addition of Li2 O. The addition of Y2 O3 is advantageous for the formation of high aspect ratio β- Si3 N4 grains. After postheat treatment, a large amount of intergranular glassy phase is removed, and the Li content in the samples is decreased. By this method, the β- Si3 N4 porous ceramic with a porosity of 54.1% and high flexural strength of 110 ± 8.1 MPa can be prepared with a small amount of sintering additives, 0.66 wt% Li2 O and 0.33 wt% Y2 O3, and it is suitable for high-temperature applications. [ABSTRACT FROM AUTHOR]