Polymer-derived ceramic-based thin film temperature sensors (TFTS) exhibit attractive potential for the temperature monitoring of critical components in aerospace. However, the fabrication of PDC-based TFTS with high performance cannot be deposited on the nonplanar surfaces conformally, facing enormous challenges. In this work, a self-adaptive direct ink writing (SADIW) device was invented to prepare thin films using polymer precursor without filler addition. The complex pattern with a minimum line-width of approximately 45 mu m can be printed on curved surfaces using SADIW device, displaying excellent flexible manufacturing and high accuracy. Meanwhile, the Hagen-Poiseuille model was proposed to analyze the printing process based on the theoretical simulation, which is conducive to facilitating the prediction of optimal printing parameters. Additionally, the fabricated SiCN TFTS exhibits great temperature sensing performance from room temperature to 800 degrees C and possesses supreme sensitivity coefficient of 17,043 at high temperature, displaying excellent repeatability and stability. The successful fabrication of the SiCN thin film demonstrated that PDCs can be prepared without adding filler, resolving the issue of performance degradation of the reported TFTS caused by structural inhomogeneity and relatively low density. The SADIW technique has promising potential for application in additive manufacturing and provides a new pathway for the development of high-performance temperature sensors on intricate surface applications.

SiC whisker-reinforced Al2O3 (SiCw-Al2O3) composites are promising candidates for high-performance applications such as cutting tools, aerospace components and high-temperature structural parts. However, their broader implementation has been constrained by limited sinterability, which detrimentally affects final microstructure and mechanical properties. Previous studies indicate that enhanced densification and performance can be achieved through pressure-assisted sintering and improved whisker dispersion. In this work, we introduce a simple yet effective processing strategy that combines regulation of powder dispersion with hot oscillatory pressing (HOP) to address these challenges. Utilizing this approach, we fabricated a SiCw-Al2O3 composite at 1500 degrees C exhibiting a near-full density of 99.1 %, an average grain size of 0.52 mu m, a hardness of 24.4 GPa, a flexural strength of 769.2 MPa, and a fracture toughness of 5.12 MPa m1/2. Analysis of sintering kinetics demonstrates that optimized whisker dispersion not only accelerates densification but also promotes grain boundary sliding (GBS). Corresponding microstructural evidence reveals that enhanced GBS effectively reduces grain boundary energy, consistent with the observed grain refinement. Thus, by synergistically tailoring powder dispersion and employing HOP, high densification can be attained at lower sintering temperatures while simultaneously refining the microstructure, reducing grain boundary energy, and significantly improving mechanical properties. This integrated approach offers a low-energy, scalable pathway for fabricating high-performance whisker-reinforced ceramic composites.

Hot oscillatory pressing (HOP) is an advanced sintering technique for producing ceramics with high mechanical performance; however, the underlying mechanism by which oscillatory pressure promotes densification and microstructural refinement remains inadequately understood. In this study, hysteresis analysis, adapted from metal fatigue models, was first applied to monitor the sintering behavior of Al2O3/TiCp composites in real time. Densification curves and hysteresis loops indicate that grain boundaries exhibit viscoelastic characteristics when grain boundary sliding dominates, and the oscillatory pressure optimizes sintering through cyclic softening and hardening. Initially, a softening process promotes grain boundary sliding to accelerate densification. As the density increases, energy dissipation due to internal friction induces a transition to cyclic hardening, thereby enabling simultaneous microstructural refinement and property enhancement. Microstructural analysis further reveals that, compared to static pressure, oscillatory pressure reduces grain boundary energy, inhibits grain growth, and enhances densification. The HOP-sintered composite exhibits a Vickers hardness of 21.8u00B10.3 GPa and flexural strength of 795u00B129 MPa, improvements of ~10% and 21.4%, respectively, over hot pressing (HP). This work establishes a mechanistic framework linking oscillatory pressure to microstructural evolution, providing theoretical support for the further development of HOP technology.

This study systematically investigated the damage evolution in cemented tailings backfill with varying initial defect levels (C1, C2, C3) using uniaxial compression tests and simultaneous acoustic emission (AE) monitoring. The temporal patterns of key AE parameters—ringing counts, amplitude, peak frequency, and energy—were analyzed. By integrating I_b value and RA-AF analysis, the influence of initial defects on damage mechanisms and failure modes was elucidated. Results show that initial defects significantly affect AE activity. Specimens with larger defects (C3) exhibited substantially higher cumulative ringing counts (> 15000 vs. 6000 for C2) and intense energy release during early loading, characterized by elevated maximum amplitudes (up to 72 dB vs. 57 dB in C2), broad frequency distributions (spanning 0–27 kHz), and pronounced I_b value fluctuations (ranging from 1.76 to 2.18). In contrast, specimens with smaller defects showed weaker AE activity and a relatively smoother failure progression. After peak stress (0.797 0.806 MPa), frequency responses declined across all specimens, corresponding to stages of crack propagation and penetration. RA-AF analysis indicated that tensile failure was dominant initially, but as loading progressed into the elastic–plastic stage, the proportion of shear cracks increased progressively. Notably, larger initial defects delayed the onset of dominant shear failure. By quantifying the coupled evolution of AE parameters and failure modes specific to defect-laden cemented backfill, this study provides a novel quantitative theoretical basis for damage assessment and stability prediction in cemented tailings backfill engineering.

ABSTRACT The demand for high‐temperature electromagnetic wave absorption (EWA) materials has significantly increased alongside advancements in aerospace and communication technologies. Although traditional magnetic absorbers, such as ferrites and metal powders, show excellent magnetic loss performance at room temperature, they have significant limitations in harsh environments due to their high density, low Curie temperature, and susceptibility to oxidation. In contrast, carbon‐containing materials have emerged as promising candidates for high‐temperature EWA applications, owing to their high melting point, low density, tunable dielectric loss mechanisms, and superior thermal stability. Unlike magnetic materials, carbon‐based systems primarily dissipate electromagnetic energy through conductance loss, dipole polarization, and interfacial polarization, thereby avoiding performance degradation at elevated temperatures. However, several critical challenges remain, including insufficient oxidation resistance, mechanical reliability issues, and the need for stable impedance matching. To address these limitations, recent strategies such as defect engineering, heterointerface construction, and metamaterial design have been proposed to enhance thermal stability and functional performance. This review provides a systematic summary of recent advances in carbon‐containing absorbers, with a focus on dielectric loss mechanisms, optimization strategies, and multiscale structural design principles. By elucidating the structure–property relationships of carbon materials, carbide ceramics, and novel carbon hybrids, this study aims to offer theoretical and technical guidance for the development of advanced high‐temperature electromagnetic wave absorbers, thereby promoting their practical applications in aerospace and telecommunications.

The inherently strong covalent and ionic bonds of ceramics severely limit their plastic formability at low temperatures, which restricts their wide applications in complex-shaped components. In this study, we demonstrate a flash-activated deep drawing approach that enables ultrafast plastic forming of 3 mol% yttria-stabilized zirconia at a low furnace temperature of 800 degrees C and a high forming speed of 8 mm/min, which represents a substantial improvement over the extreme conditions typically required in conventional ceramic forming (1450-1750 degrees C, <0.6 mm/min) and other field-assisted forming studies (1400-1600 degrees C, similar to 0.1 mm/min). Furthermore, regionspecific forming experiments indicate that the anode and middle regions of the sample show better formability than the cathode region, owing to higher local temperatures and fewer vacancy-related defects. The abundant dislocations suggest that deformation is governed by dislocation-accommodated grain-boundary sliding, with electric field/current-enhanced diffusion further promoting grain-boundary accommodation and acting synergistically with dislocation activity.

Abstract Hot oscillatory pressing (HOP) is an advanced sintering technique for producing ceramics with high mechanical performance; however, the underlying mechanism by which oscillatory pressure promotes densification and microstructural refinement remains inadequately understood. In this study, hysteresis analysis, adapted from metal fatigue models, was first applied to monitor the sintering behavior of Al2O3/TiCp composites in real time. Densification curves and hysteresis loops indicate that grain boundaries exhibit viscoelastic characteristics when grain boundary sliding dominates, and the oscillatory pressure optimizes sintering through cyclic softening and hardening. Initially, a softening process promotes grain boundary sliding to accelerate densification. As the density increases, energy dissipation due to internal friction induces a transition to cyclic hardening, thereby enabling simultaneous microstructural refinement and property enhancement. Microstructural analysis further reveals that, compared to static pressure, oscillatory pressure reduces grain boundary energy, inhibits grain growth, and enhances densification. The HOP-sintered composite exhibits a Vickers hardness of 21.8±0.3 GPa and flexural strength of 795±29 MPa, improvements of ~10% and 21.4%, respectively, over hot pressing (HP). This work establishes a mechanistic framework linking oscillatory pressure to microstructural evolution, providing theoretical support for the further development of HOP technology.

Extreme-high-temperature dielectric characterization is challenging and costly. In this work, the spoof localized surface plasmons (SLSPs) are introduced for the detection of high-temperature dielectric constant of ceramic materials. Confinement of electromagnetic fields and strong correlation between multiple modes of SLSPs are investigated to reduce random errors in characterizing lossy materials. This method is validated through testing on Rogers materials and further applied in harsh environments to measure the permittivity of alumina at the temperature up to 1250 °C after correction of thermal strain. This proposed method is accurate, convenient and low-cost, possessing great potentials for in aerospace and other fields.

Previous studies on the creep behavior of ceramic materials were primarily conducted under static loads. However, the majority of applications for ceramic materials are subject to dynamic loads, and there is a paucity of research conducted in this area. In this work, we report for the first time the creep behavior of Al2O3 whisker-reinforced ZrO2 composites under dynamic pressure. The results showed that the sample crept under dynamic pressure produced higher creep rate and lower activation energy compared to static pressure. By analyzing the creep data and microstructures, we showed that the dynamic pressure can enhance dislocation motion and transform the creep mechanism from diffusion-controlled grain-boundary sliding to dislocation-controlled grain-boundary sliding. This work provides a foundation for subsequent detailed studies of the creep behavior of ceramic materials under dynamic pressure.

Designing in situ whiskers to enhance the fracture toughness of ceramics presents challenges for structural applications. Herein, two corundum‐type medium‐entropy oxide ceramics (MEO‐1 and MEO‐2) are synthesized through solid‐state reaction sintering under controlled oxygen partial pressures. MEO‐1 is a single‐phase corundum‐type oxide (Al 0.41 Cr 0.26 Fe 0.31 Ti 0.02 ) 2 O 3 , while MEO‐2 incorporates (Fe 4 Al 3 Cr) 0.25 TiO 5 whiskers to reinforce (Al 0.40 Cr 0.25 Fe 0.30 Ti 0.05 ) 2 O 3 . By regulating variable valence ions at different oxygen partial pressures, the whiskers achieved a maximum average length of 28.3 µm and a length‐to‐diameter ratio of 17.7 at 50.6 kPa, significantly enhancing the fracture toughness of the MEO‐2, which possesses the optimal flexural strength, Vickers hardness, and fracture toughness of 321 ± 8 MPa, 22.4 ± 1.5 GPa, and 3.87 ± 0.12 MPa m 1/2 , respectively. Bravais–Friedel–Donnay–Harker law (BFDH) simulation elucidates that oxygen partial pressures can effectively regulate ionic diffusion behavior and whisker growth. First‐principles calculations demonstrate that the whisker growth direction [0 4 0] aligns with the high shear modulus direction, contributing to the strengthening mechanism. This work provides new insights for designing high‐performance medium/high‐entropy ceramics, highlighting the critical role of oxygen partial pressure in regulating whisker growth and improving mechanical properties.

The coordinated metal single-atoms (MSA) can significantly enhance the electromagnetic wave (EMW) absorption properties of materials through adjusting local electron structure and polarization relaxation. The symmetric electronic environments for EMW absorption have been extensively studied, but the asymmetric electron dispersion from an atomic-scale perspective is blurring puzzle. In this work, the amorphous polymerderived SiZnCN ceramics with porous "Cheese" structure were prepared by regulating Zn coordination and pyrolysis temperature. The SiZnCN (15 wt% ZnAc doping) ceramics pyrolyzed at 1400 degrees C exhibits an effective absorption bandwidth (EAB) of 4.96 GHz at an ultrathin thickness of 1.28 mm. This SiZnCN ceramics after oxidized at 500 degrees C still possesses excellent high-temperature EMW absorption performance. Benefiting from the porous structure and coordinated single Zn atoms, the asymmetric electronic environment in amorphous SiZnCN ceramics is established, promoting electron/dipole and interfacial polarization. This work proposes an effective strategy to optimize electromagnetic wave absorption for high temperature by coordinating asymmetric electronic environments in disordered structures.

Traditional silicon-based pressure sensors cannot meet demand of pressure information acquisition in high-temperature extreme environments due to their low sensitivity, limited detection temperature and complex processing. Herein, a capacitive pressure sensor is fabricated using polymer-derived SiCN ceramics with convex microstructures via a sample replication strategy. Its performance is measured at different pressures (0-800 kPa) from room temperature to 500 degrees C. The results show that the SiCN ceramic capacitive pressure sensor exhibits low hysteresis, good non-linearity of 0.26 %, outstanding repeatability and high sensitivity of 0.197 pF/MPa under room temperature. When the test temperature reaches 500 degrees C, the performance of the prepared capacitive pressure sensor has no degradation, keeping competent sensitivity of 0.214 pF/MPa and nonlinear error of 0.24 %. Therefore, benefitting from the preeminent high-temperature properties, e.g., excellent oxidation/corrosion resistance and thermal stability, SiCN ceramics capacitive pressure sensors have great potential in the application of high-temperature and harsh environments.

This study was the first to investigate the influence of high‐pressure sintering (HPS) on the electrical conductivity of polymer‐derived SiCN ceramics (PDCs‐SiCN). The results showed that at the same temperature conditions (1000°C), the electrical conductivity of PDCs‐SiCN produced through high‐pressure sintering (SiCN‐HPS) was over 185 times higher than that of produced by conventional sintering (CS) in a furnace. X‐ray diffraction (XRD) patterns confirmed that both samples retained an amorphous structure without noticeable crystallization. Chemical composition, Raman spectroscopy and transmission electron microscopy (TEM) analyses revealed that HPS not only promoted the precipitation of free carbon in PDCs‐SiCN but also significantly increased its ordering. Furthermore, compared to SiCN‐CS, the SiCN‐HPS exhibited a significantly increased density (2.59 g/cm 3 ) and reduced porosity (0.54%). These results demonstrated that HPS effectively regulated the amount, distribution, and structure of free carbon within PDCs‐SiCN, while reducing the formation of insulating pores, which substantially improved conductivity. In addition, the SiCN‐HPS also exhibited excellent temperature‐resistance response, highlighting HPS as a promising strategy for developing high‐performance silicon‐based engineered PDCs.

Inherent inferior plasticity of ceramic composites hinders severely the improvement of mechanical properties via increment of dislocation density and transformation of morphology by post-treatment. To date, dynamic hot forging (DHF) is discovered as a direct and efficient strategy to promote deformation and dislocation density in ceramics. Herein, we forge the Al2O3 whisker reinforced ZrO2 composite via DHF and systematically study the effect of dynamic pressure amplitude on the microstructure regulation and mechanical properties. The results show that dynamic pressure can produce intragranular dislocations in the composite, and thus leading to plastic deformation via dislocation-accommodated grain-boundary sliding. Furthermore, the vibration of pressure amplitude can significantly promote dislocation density, and thereby resulting in regulation of dislocation morphology and interior microstructures. The corresponding mechanical properties of the composite is also significantly improved by DHF process. This work provides a novel pathway for regulating microstructures and improving mechanical properties of ceramic composites via DHF.

The low-temperature plastic forming ability of ceramics with complex structures is unsatisfied due to the strong covalent and ionic bonds, restricting their widespread applications. Herein, a technique is proposed for the ultra-fast plastic forming of zirconia ceramics using a low temperature and high electric field. The high electric field-assisted plastic forming temperature and rate are 1000 degrees C and 10 mm/min, respectively, which are much lower and faster than those of conventional plastic forming methods for ceramics. The deformed "Omega"-shape zirconia part exhibits a uniform microstructure without microcracks/cavities and a high hardness, demonstrating that the high electric field-assisted plastic forming technique enables the rapid fabrication of complex ceramic components with beneficial properties at low temperatures.

Understanding the structural evolution and enhancement of electrical conductivity in polymer-derived SiCN ceramics under high-temperature and high-pressure (HTHP) conditions is essential for enabling their deployment in harsh or extreme service environments. In this work, we systematically investigated the coupled influence of temperature (1000-1500 degrees C) and pressure (5 GPa) on the crystallization behavior and electrical properties of SiCN ceramics using integrated XRD, Raman, XPS, and TEM analyses. HTHP sintering led to a six-order-ofmagnitude increase in electrical conductivity (from 7.75 x 10(-7) S/cm to 6.1 x 10(-1) S/cm) under HTHP sintering, primarily attributed to the progressive graphitization of free carbon, evolving from amorphous clusters into highly ordered, needle-like graphite. In addition, pressure-assisted crystallization promoted the formation of alpha- and beta-Si3N4 phases at temperatures above 1300 degrees C. Raman and XPS analyses confirmed the sp3 to sp2 carbon transition and the concurrent cleavage of Si-C bonds. Meanwhile, TEM observations revealed transformation of carbon-rich regions (3-5nm) into needle-like graphite, as well as the coexistence of amorphous and crystalline Si3N4. Our results indicate that elevated temperature predominantly promotes the nucleation and growth of crystalline grains, whereas pressure enhances nucleation while simultaneously suppressing atomic diffusion, resulting in finely dispersed nanocrystalline structures. This study provides a mechanistic framework for tailoring the electrical and structural properties of polymer-derived ceramics, and advances their application in nextgeneration high-temperature sensors and electromagnetic shielding materials.

Chromium -51 ( 51 Cr) is an attractive radionuclide for diagnosis, which is usually applied for red cells and platelet radiolabeling. However, commercially available 51 Cr produced in nuclear reactors via neutron activation requires long irradiation times and complex separation methods. In this work, five metal -organic frameworks (MIL -100 (Cr), MIL -100 (Fe), MIL -100 (Al), MIL -101 (Cr) and aluminium fumarate MOF (FuAl)) were synthesized and the effect of gamma ray irradiation with a high dose rate and a maximum dose of 6 MGy was investigated. The two chromium -based MOFs, MIL -100 (Cr) and MIL -101 (Cr), were selected as radiation targets to produce high specific activity 51 Cr by the Szilard-Chalmers effect. A solid -liquid extraction was applied to extract the produced 51 Cr under different conditions, including different extractants, extraction times and pH. The most promising results were achieved when using irradiated MIL -101 (Cr) and EDTA as extracting agent, reaching an enrichment factor of 1132 +/- 50.

To overcome the problem of insufficient molybdenum adsorption capacity of commercially utilized alumina in 99Mo/99mTc generator, UiO-66(Ce)@MXene composites as potential molybdenum adsorbents were successfully prepared via in-situ growth method in this work. The adsorption performance and adsorption mechanism were investigated. The results indicate that the UM3 possesses superlative adsorption behavior compared to the other two samples. The adsorption kinetics are well described by the quasi-second-order model and the adsorption reaches equilibrium within 30 min. The adsorption isotherm can be well fitted with the Langmuir model, displaying the maximum molybdenum adsorption capacity of 833 mg/g at pH 3, superior to other reported adsorbents. The adsorption capacity manifests that polymolybdates are captured by the hydroxyl groups on MXene through hydrogen bonds. The monomolybdates can diffuse into micropores and are adsorbed on adsorption sites, e.g. missing-linker defects and Ce-OH groups. Consequently, the constructed hierarchical frameworks promote molybdenum adsorption and increase adsorption capacity significantly. The unrivalled adsorption performance of UiO-66(Ce)@MXene composites as molybdenum adsorbents have promising potential for the application in 99Mo/99mTc generator.

Designing multifunctional integrated composites is a viable approach to meet the diverse requirements in complex environments. By incorporating microwave absorption capability into mullite insulation tiles, it becomes feasible to simultaneously achieve both microwave absorption and thermal insulation effectiveness within a single system, thereby enhancing the materials' adaptability and efficiency. In this study, mullite insulation tiles were utilized as support structures, and polymer‐derived SiCN (PDC‐SiCN) ceramic aerogel with microwave absorption properties was loaded onto the mullite through the high‐pressure impregnation‐pyrolysis technique to fabricate SiCN/mullite insulation tile composite (SM composite). With the inclusion of SiCN aerogel, the SM composite, after one impregnation‐pyrolysis cycle, exhibited exceptional microwave absorption performance, whose minimum reflection loss was −49.24 dB (99.99% microwave absorption) at 15.84 GHz, and effective absorption bandwidth was 9.23 GHz. Additionally, due to the synergistic effect between mullite and SiCN aerogel, the SM composite demonstrated significantly reduced thermal conductivity in 25–1000°C (.064–.086 W·m −1 ·K −1 ), much lower than that of mullite insulation tiles (.076–.156 W·m −1 ·K −1 ). The superior combination of excellent microwave absorption and low thermal conductivity properties makes the SM composite an ideal stealth/thermal insulation integrated material in a thermal protection system operating in a high‐temperature environment.