Silicon carbide (SiC) aerogels represent an emerging class of multifunctional materials that integrate a three-dimensional (3D) porous architecture with the intrinsically superior physicochemical properties, exhibiting considerable promise for thermal insulation and electromagnetic wave (EMW) absorption under extreme environments. This review systematically summarizes recent advances in the fabrication strategies, structure-property relationships, and functional performance of SiC aerogels. For thermal insulation, the highly porous framework effectively suppresses solid-state heat conduction and gas convection, while the wide bandgap semiconducting nature of SiC enables efficient thermal radiation attenuation, collectively ensuring excellent insulation stability at elevated temperatures. SiC aerogels deliver broadband and strong absorption through a combination of moderate electrical conductivity, abundant interfacial polarization, optimized impedance matching, and multiple scattering within the 3D porous network with respect to EMW absorption. Moreover, recent studies demonstrate that synergistic enhancement of thermal insulation and EMW absorption can be achieved via multicomponent compositional engineering, hierarchical structural design, and advanced fabrication techniques, thereby accelerating the deployment of SiC aerogels in frontier applications including aerospace, defense systems, and thermal management for emerging energy technologies.

Hydrogen sulfide (H₂S) poses a significant threat to human health even at trace levels. Rapid and reliable H₂S detection with high sensitivity is of paramount importance. Herein, copper oxide and tin dioxide comodified reduced graphene oxide (CuO/SnO₂/RGO) composite nanosheets (CSRs) were synthesized via a one-step microwave-assisted method and used as functional sensing layers for H₂S detection. The composite consists of secondary CuO and SnO₂ nanoparticles, grown in situ and uniformly anchored onto the reduced graphene oxide (RGO) surfaces. The 3-CSR composite with a Cu : Sn molar ratio of 3 : 7 has a particle size range from 6.3 to 25.1 nm with an average diameter of 11.8 nm. The formation mechanism stems from the initial coordination of Sn²⁺ and Cu²⁺ ions with the oxygen-containing functional groups on the graphene oxide (GO) surface. The CSR sensor demonstrates an exceptional sensing response to H₂S, which is significantly modulated by the Cu/Sn molar ratio. The optimized 3-CSR composite exhibits superior gas-sensing properties, achieving a remarkable response of 28,233 toward 50 ppm H₂S with an ultrafast response time of merely 2 s at a low operating temperature of 80 °C. The enhanced performance is attributed to the synergistic effects of numerous p–n heterojunctions, together with the high RGO network, high specific surface area, and oxygen vacancy defects, which promote gas adsorption and charge transfer.

Carbides are considered promising candidates for advanced manufacturing applications due to their superior mechanical properties and excellent thermal stability. However, the requirement for high sintering temperatures remains a significant barrier to achieving dense microstructures with refined grain sizes. In this work, high-entropy (TiVNbTaMo)C_4.5 ceramics with a fine average grain size of ~ 434 nm and high relative density were successfully synthesized at a relatively low temperature of 1550 °C via spark plasma sintering. The pronounced reduction in both sintering temperature and grain size is attributed to the high-entropy effect and the lattice distortion introduced by incorporating multiple principal elements with different crystal structures. The resulting ceramics exhibit a high flexural strength of 813 MPa and a Vickers hardness of 39.19 GPa, without sacrificing fracture toughness, thereby overcoming the typical trade-off between hardness and toughness. The effects of grain refinement and solid–solution strengthening on mechanical properties are systematically investigated using advanced microstructural characterization techniques. This study demonstrates an efficient and cost-effective strategy for the fabrication of high-performance high-entropy (TiVNbTaMo)C_4.5 carbide ceramics.

Multifunctionalization is the development direction of personal thermal energy regulation equipment in the future. However, it is still a huge challenge to effectively integrate multiple functionalities into one material. In this study, a simple thermochemical process was used to prepare a multifunctional SiC nanofiber aerogel spring (SiC NFAS), which exhibited ultralow density (9 mg/cm³), ultralow thermal conductivity (0.029 W/(m·K) at 20 ℃), excellent ablation and oxidation resistance, and a stable three-dimensional (3D) structure that composed of a large number of interlacing 3C-SiC nanofibers with diameters of 300-500 nm and lengths in tens to hundreds of microns. Furthermore, the as-prepared SiC NFAS displayed excellent mechanical properties, with a permanent deformation of only 1.3% at 20 ℃ after 1000 cycles. Remarkably, the SiC NFAS exhibited robust hyperelasticity and cyclic fatigue resistance at both low (~ -196 ℃) and high (~700 ℃) temperatures. Due to its exceptional thermal insulation performance, the SiC NFAS can be used for personal thermal energy regulation. The results of the study conclusively show that the SiC NFAS is a multifunctional material and has potential insulation applications in both low- and high-temperature environments.

Ultra-large zirconia toughened alumina (ZTA, mass ratio of Al₂O₃ and ZrO₂ is 78:22) ceramics with eccentric circle shape were successfully sintered by microwave sintering with a multi-mode cavity at 2.45 GHz. The dimension of ZTA ceramics (green body) is 165 mm (outer diameter) × 25 mm (thickness). The optimized sintering temperature of microwave sintering is about 1500 ℃ for 30 min, and the total sintering time is about 4 h which is much shorter than that of conventional sintering. An auxiliary-heating insulation device was designed based on the principle of local caloric compensation to guarantee the intact sintered samples. With the increasing of sintering temperature, more and more microwave energy is absorbed within the entire sample, volumetric densification performs, and phases shift from m-ZrO₂ phase to t-ZrO₂ phase and cause Al₂O₃ grain growth.