To mitigate the formation of a porous oxide layer in a single HfC coating during long-term ablation, this work employed chemical vapor deposition to fabricate solid-solution HfxZr1-xC coatings on SiC-coated C/C composites. The microstructure, thermal properties, and ablation behavior of these coatings were investigated through experimental and first-principles calculations. Results indicated that all coatings exhibit a single-phase NaCl-type solid solution structure with uniform elemental distribution. As the Zr content increases, the coefficient of thermal expansion of the HfxZr1-xC coating increases, while the enhanced lattice distortion leads to reduced thermal conductivity. After proportional regulation, the mass and linear ablation rates of the Hf0.5Zr0.5C coating are reduced by 40.98 % and 46.15 %, respectively, after ablation for 180 s at 2300 degrees C. The formation of a dense and uniform Hf0.5Zr0.5O2 solid-solution oxide layer enhances the ablation resistance, which is attributed to its compositional homogeneity and the fusion of grain boundaries during ablation, thereby effectively suppressing oxygen diffusion and promoting more cooperative oxygen transport. This study indicates that solid-solution structure ceramic coatings hold promising prospects for application in the field of ultra-high-temperature thermal protection. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Ultra-high temperature thermal protective materials (UHTPMs), endowed with exceptional temperature resistance, high mechanical strength, and superior corrosion resistance, have emerged as critical materials in fields of aerospace, nuclear energy, and advanced equipment manufacturing. Recently, driven by the dual impetus of the worsening global energy crisis and the continuous advancement of aircraft performance, UHTPMs are gradually evolving toward lightweight and long service life. Conventional materials have been increasingly unable to meet the current stringent demands, making the upgrading of material systems an urgent necessity. The intrinsic properties of UHTPMs are core indicators that directly measure their service stability and reliability. Advanced characterization technologies serve as the key to material screening. Moreover, the correlation between “composition-structure-process-property” will be essentially established only by systematic elucidation of their thermal protective mechanisms. Therefore, this review highlights the recent progress in advanced characterization techniques and investigation methodologies for thermal protective mechanisms of UHTPMs, aiming to provide theoretical guidance and technical references for the development of new high-performance UHTPMs.

As an environmental barrier coating (EBC) for carbon/carbon (C/C) composites, rare earth silicates can effectively resist the erosion of water vapor and oxygen in high-temperature environments. The (Yb1-xScx)2Si2O7 (x = 0.25, 0.5 and 0.75) solid solution materials were prepared by solid sintering method. The influence laws of Sc doping ratio on microstructure, mechanical properties and resistance to water-oxygen corrosion were investigated. All prepared solid solutions are dominated by β-(Yb1-xScx)2Si2O7 matrix. Trace monosilicate impurity can only be observed in high-Sc (Yb0.25Sc0.75)2Si2O7 sample. The (Yb0.25Sc0.75)2Si2O7 presented the highest hardness and elastic modulus. Among all samples, the (Yb0.75Sc0.25)2Si2O7 solid solution exhibited the most excellent water-oxygen corrosion resistance, making it an ideal material for environmental barrier coatings. The (Yb0.75Sc0.25)2Si2O7 coating was prepared on SiC-coated C/C composites by slurry brushing method. However, the coating failed with a 3.853% weight loss after 120 h of water-oxygen corrosion at 1500 °C in 90% H2O-10% O2. The failure of (Yb0.75Sc0.25)2Si2O7 coating is due to the water-oxygen environment causing the coating to become and porous.

This paper presents a novel approach combining numerical simulations and experiments to evaluate the mechanical behaviors of ring-shaped throat backups reinforced with needled C/C composites in solid rocket motors under room and high temperatures. First, the fracture pattern of the ring is examined experimentally. On this basis, a multiscale homogenization method is used to integrate microstructural features into a macroscale model by passing homogenized temperature-dependent material properties. The macroscale model is established according to the experimental condition, and combines the Tsai-Wu failure criterion for initiation and an instantaneous stiffness reduction method for evolution. Meanwhile, zero-thickness cohesive elements are employed to obtain fracture behaviors within the ring. Validation against experimental results demonstrates the predicted relative errors are both below 12.22 % for the critical load and displacement. Furthermore, investigations into the effects of the wall thickness and aspect ratio (beta) indicate that the peak load and compressive stiffness go up as the wall thickness or beta rises at 1200 degrees C. The results show that the ultimate load increases nearly 25-fold as the wall thickness grows from 1 mm to 5 mm, while it increases by 34.69 % as the beta rises from 0.86 to 1.2. Additionally, the ring length has little significant influence on the critical displacement. These findings provide theoretical guidance for the design and optimization of needled C/C composite ring-shaped parts.

Understanding the physicochemical processes in a Si-C-ceramics system is crucial for anti-oxidation coatings prepared by the slurry method and gaseous silicon infiltration (GSI). This paper investigated the effect of dual distributions of carbon in the pre-coatings, including the carbon black distributed between ceramic particles and the pyrolytic carbon (PyC) shell covering the SiC whisker (SiCw), on the microstructures of the ZrB2-SiC-Si-SiCw coatings treated by the GSI and their oxidation performances at 1973 K. The addition of 8.1 wt% carbon black facilitates the morphological retention of SiCw after the GSI. Furthermore, the deposition duration of the PyC shell affects microstructures and phase distributions of the coatings. Notably, the heat released from the C-Si reaction promotes the condensation of gaseous silicon, and the detection of ZrSi2 provides evidence for the mass transfer of element Zr assisted by silicon melt. For the PyC deposition duration of 2 h, the obtained ZrB2-SiC-SiSiCw coating shows an optimal oxidation protection ability at 1973 K, protecting the C/C composites for 37 h with a mass gain of 0.27%. The stable oxide layer is attributed to the reinforcement of SiCw, and uniformly distributed ZrB2 within the GSI-treated coating, which turns to ZrO2 skeleton pinning SiO2 during oxidation.

High-entropy carbide ceramics (HECCs) possess promising properties for extreme high-temperature applications. Machine learning offers an effective pathway to accelerate the discovery of novel HECCs, but data imbalance poses challenges for predictive performance. Here, we integrate the Borderline-SMOTE with machine learning algorithms to address this issue. A dataset containing 251 samples was established from literature, experimental synthesis, and synthetic oversampling. Key features influencing phase formation were selected via a four-step feature selection strategy. Ten common machine learning models were trained and optimized, with the random forest (RF) model identified as the most suitable for predicting HECCs phase formation ability. Eight HECCs compositions with high uncertainty were experimentally validated, and the results were incorporated back into the dataset to iteratively improve model accuracy. This work provides an efficient strategy for predicting phase formation in HECCs, particularly for small or imbalanced datasets, facilitating the accelerated design and reliable prediction of new HECCs.

Hypersonic thermal protection requires materials with thermal shielding and electromagnetic wave absorption capabilities. While silicon carbide (SiC) aerogel is a promising candidate due to their dielectric properties, porosity, and thermal stability, the conventional forms face an intrinsic trade-off between microwave absorption and thermal insulating. Inspired by natural hollow structure of reeds, this work proposes a novel in-situ growth technique combined with a sacrificial-template process to fabricate a lightweight SiC-based composite aerogel featuring a unique hollow microtube-nanowire hybrid architecture (SCN-SCH). Impressively, the hollow microtubes, in synergy with the nanowire network and optimized SiC content, contribute to enhanced electromagnetic wave absorption through improved impedance matching and abundant heterogeneous interfaces. Crucially, this hollow architecture achieves substantially improved insulation performance while preserving the ultralow density (0.038 W/(m & sdot;K) thermal conductivity) and mechanical robustness (70% compressibility, resilience over 50 cycles) of the aerogel. Moreover, this multiscale structure of SCN-SCH aerogel delivers a broadband absorption band extending to 3.9 GHz at a thickness of 2.6 mm and a minimum reflection loss of -59.37 dB. This study not only provide a bioinspired multiscale engineering strategy of SiC aerogels to effectively improve the conflict between thermal insulation and microwave absorption, but also offers a new design paradigm for high-performance multi-functional materials in extreme environments.

Carbon fiber reinforced phenolic resin composites (CF/PR) are promising for multifunctional structural applications but are limited by weak fiber-matrix interfacial bonding. Herein, we report an interface engineering strategy to tailor the fiber/matrix interphase by constructing a multilayered graphene-pyrolytic carbon-graphene (GE-PyC-GE) structure on the carbon fiber surface via sequential CVD processes. The effects of this designed interphase on the microstructure, mechanical properties, tribological behavior, EMI shielding performance, and thermal conductivity were systematically investigated. Results show that the GE-PyC-GE multilayered interphase significantly enhances fiber-matrix interlocking and load transfer efficiency. Compared with unmodified composites, the tensile strength increased by 43%, while the wear rate decreased by 68%. The abundant interfaces promote multiple reflections of electromagnetic waves, yielding a 45% enhancement in EMI shielding effectiveness (reaching 37 dB) in the X-band. Additionally, reduced interfacial thermal resistance leads to a 33% improvement in thermal conductivity. This work demonstrates an effective interface engineering strategy for developing high-performance multifunctional carbon fiber composites.

Improving the ablation resistance of carbon/carbon (C/C) composites in high-temperature oxidative environments is critical to the effective design of thermal protection systems in aerospace applications. However, the exploration of the matrix ablation behavior of C/C composites has received limited attention in existing research. In this study, two types of 2.5D needle-punched preforms were designed through structural optimization for C/C composites, using mesophase-pitch-based carbon fiber (CFMP) and polyacrylonitrile-based carbon fiber (CFPAN) as reinforcements, respectively. Subsequently, 2.5D CFMP/C-ZrC-SiC and 2.5D CFPAN/C-ZrC-SiC composites, serving ZrC and SiC as the ablation-resistant ceramic phases, were fabricated via a combined process of chemical vapor infiltration (CVI) and precursor impregnation pyrolysis (PIP). Benefiting from the high thermal conductivity of CFMP, 2.5D CFMP/C-ZrC-SiC composites exhibited a thermal conductivity of 87.30 W/m*K at room temperature. Under high-temperature ablation conditions, its surface temperature was reduced by a maximum of 200 degrees C compared with that of 2.5D CFPAN/C-ZrC-SiC composites. On this basis, a 3D CFMP punctured preform was designed to further explore the effect of the preform structure on the ablation performance. The improvements in thermal conductivity and mechanical properties conferred by the 3D structure further enhanced the ablation resistance of CFMP/C-ZrC-SiC composites. The composite exhibited linear and mass ablation rates of 1.983 mu m/s and 1.776 mg/s, respectively, providing a valuable reference for the design of thermal protection systems for hypersonic vehicles and structural materials used in extreme environments.

Wet friction materials are essential components in the transmission and braking systems of high-end equipment. However, their performance is often limited by weak interfacial adhesion between the carbon fibers and the resin matrix. In this study, zirconium-based metal-organic frameworks (MOFs), namely UiO66-NH2, are grown on the surface of carbon cloth via an in-situ solvothermal method. With the carbon fibers themselves acting as the support skeleton and core reinforcement of the entire structure, a unique organic-inorganic interwoven 3D porous network is constructed. By precisely controlling the concentration of acetic acid, we effectively tuned the morphology and distribution of the UiO66-NH2 crystals on the fiber surface. This interwoven structure creates abundant micromechanical interlocking sites and robust interfacial adhesion via combined physical and chemical interactions. By doing so, it facilitates efficient stress transfer, alleviates stress concentration, and effectively inhibits crack propagation. The results show that the modified sample, CFs/UiO66-NH2-6, had a 68.8 % increase in tensile strength to 513.61 MPa, a rise in the friction coefficient from 0.088 to 0.115, and a 71.8 % reduction in wear rate, all while maintaining highly stable friction performance. Our research offers an innovative and effective strategy for designing high-performance wet friction materials with superior mechanical and tribological properties.

Composite materials with gradient structures are ideal candidates for high-temperature thermal protection systems of aerospace vehicles due to their unique properties within distinct regions. Herein, we report a novel method of localized filtrating modification (LFM) for fabricating gradient materials, offering a lightweight design and exceptional thermal protection performance. Notably, the gradient structure results in a density reduction of 37 % and a linear ablation rate of only 1.43 mu m s(-1) after 120 s ablation, which is 75 % lower than that of uniform composites attributed to the reduced heat accumulation at the ablation center. Additionally, the particle refinement by LFM and the self-healing effect of the oxides of (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C prevent the failure of the produced oxide barrier layer. In this work, lightweight gradient composites that can withstand elevated temperatures with excellent thermophysical properties and ablation resistance are developed, providing a universal and adaptable strategy for the design and fabrication of advanced functional gradient materials.

Silicon carbide nanowires (SiCnws) are promising microwave absorbers, yet their performance is limited by a low dielectric constant and a lack of magnetic loss. While doping offers a potential solution, controlling doping levels in SiCnws remains challenging, and its effect on absorption performance is unclear. In this study, we developed a simple chemical vapor deposition (CVD) method to prepare nitrogen-doped SiCnws with tunable nitrogen content on carbon fiber cloth. By adjusting the nitrogen amount, the microstructure and electromagnetic parameters of SiCnws could be regulated, and their effect on the electromagnetic wave absorption ability was further investigated. Surprisingly, the absorption capacity of SiCnws decreased with increasing nitrogen content. Compared to nitrogen-doped SiCnws, undoped SiCnws exhibited the best absorption performance, achieving an effective absorption bandwidth of 4.17 GHz (13.83-18 GHz, 1.30 mm thickness) and a minimum reflection loss of -37.15 dB (1.40 mm thickness). This unexpected trend is attributed to the imbalance between dielectric constant and magnetic permeability caused by small atom doping. This study not only provides a simple method for regulating the nitrogen doping levels in SiCnws but also offers insights for the development of SiCnws-based microwave absorbers.

This work fabricates a high-performance SiCf/Si3N4-SiC-Si3N4 composites by architecting a sandwich-structured matrix, where continuous SiC fibers serve dual roles as structural reinforcement and electromagnetic loss medium. In this composites, the outer Si3N4 layer promotes impedance matching, while the integrated contributions from SiC fibers, multi-heterogeneous interfaces, and free carbon significantly enhance dielectric loss. Specifically, the low-density (1.33 g/cm3) composites exhibit strong, broad-band absorption in the X and Ku bands, with a minimum reflection loss (RLmin) of -68.55 dB, an effective absorption bandwidth (EAB) of 6.89 GHz, and a flexural strength of 25.76 MPa. As the porosity decreases from 45.6% in S1 to 13.8% in S4, the RLmin and EAB of the composites decrease to -44.13 dB and 5.30 GHz, respectively. The flexural strength significantly increases to 380.53 MPa, achieving a good balance between absorption and mechanical properties. Notably, after oxidation at 1000 °C for 2 hours, S4 achieves -70.19 dB (>99.99999% absorption rate) of RLmin and 5.06 GHz of EAB. Simultaneously, the flexural strength is maintained at 227.45 MPa. The SiCf/Si3N4-SiC-Si3N4 composites developed in this work combines low density, high-temperature tolerance, high strength and broad-band strong absorption, providing a new strategy for achieving multifunctional applications of ceramic matrix composites.

The increasing challenges of electromagnetic interference and radiation pollution urgently demand the development of advanced electromagnetic wave absorption materials with excellent high-temperature stability. Medium-and high-entropy ceramics, owing to their tunable compositions and unique high-entropy effects, have attracted growing attention. In this work, novel core-shell structured (Zr, Ta, Ti)C@C ceramics were successfully synthesized via a combination of polymer-derived ceramics method and solvothermal reaction. The microstructural evolution, carbon shell formation mechanism, dielectric properties, and electromagnetic wave absorption performance of (Zr, Ta, Ti)C@C were systematically investigated. The results show that the (Zr, Ta, Ti)C/paraffin composites achieve a minimum reflection loss (RLmin) of-57.19 dB at a thickness of 1.92 mm, with an effective absorption bandwidth (EAB) of 3.62 GHz at a filler loading of 40 wt.%. With the formation of the carbon shell, (Zr, Ta, Ti)C@C/paraffin composites maintains an outstanding RLmin of-57.11 dB and achieves full X-band coverage with only 20 wt.% filler loading. The construction of the carbon shell effectively enhances interfacial polarization and dielectric loss, optimizes impedance matching, and thus significantly boosts the electromagnetic wave absorption performance. This study provides a promising strategy for designing high-performance core-shell structured medium-entropy ceramics for electromagnetic absorption applications. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Cu-modified C/C-ZrC composites are promising for thermal protection due to combined passive and active ablation resistance. However, the influence of preform orientation on Cu and ceramic distribution and ablation behavior is unclear, especially for 2.5D needle-punched fiber preform. In this work, Cu-modified C/C-ZrC composites were fabricated via reactive melt infiltration by varying infiltration direction and Cu powder placement using 2.5D needled preforms. Under XY-direction infiltration, Cu showed a fluctuating distribution with obvious local enrichment. This behavior was related to the relatively high through-thickness infiltration resistance. In contrast, Z-direction infiltration favored directional Cu migration. When combined with bottom Cu powder placement, it further produced a relatively stable through-thickness Cu gradient. Under an oxy-acetylene heat flux of 4.2 MW/m2, the gradient-structured composite exhibited the lowest surface temperature and the lowest linear and mass ablation rates, while maintaining superior structural stability during both initial and cyclic ablation. Microstructural observations suggest that this improvement is related to a more stable oxide layer, reduced crack propagation, and better interfacial integrity between the oxide scale and substrate. Overall, preform orientation directly governs component distribution and ablation performance in Cu-modified C/C-ZrC composites, with the gradient structure offering enhanced thermal protection for extreme environments.

The development of ultrahigh-temperature thermal protection materials (TPMs) with long-term ablation resistance is crucial for high-speed aircraft, where surface heat accumulation and protective layer instability remain key limiting factors for service lifetime. Ultrahigh-temperature TPMs face a critical challenge in balancing active cooling and passive protection during long-term servicing. Inspired by human skin’s thermoregulation and tree rings’ functional partitioning, we present a dual-biomimetic structural design strategy for carbon/carbon (C/C) composites that overcomes this limitation. Through a novel selective-area reactive melt infiltration method and design of thermal conductive rods, we engineered bioinspired C/C composites featuring: (1) high-thermal-conductivity Cu channels mimicking hair shafts for enhanced heat dissipation, (2) a functional partitioning architecture effectively mitigating thermal stress with an ablation-resistant ZrC-Cu core and sweat-cooling SiC-Cu-CuxSiy periphery, and (3) highly stable oxide protective film at ablation surface. This dual-biomimetic structure design synergistically reduces surface heat accumulation and surface temperature (active cooling via heat conduction and dissipation), and promotes a formation of La-stabilized oxide films (relying on regulating the phase transition), enabling the bioinspired C/C composites to achieve thermal protection for 720 s with negligible ablation damage at a high heat flux of 4.18 MW/m2 and a temperature exceeding 2400 °C, which surpass most reported C/C-based TPMs. Our work establishes a new paradigm for designing long-duration TPMs through bioinspired multifunctional integration, with broad implications for aerospace applications and extreme environment materials.

A Si-SiO2/SiC-SiCw-Si bilayer anti-oxidation coating was prepared on C/C composites by the slurry method, chemical vapor deposition joint gaseous silicon infiltration. The specimen got a mass loss of 1.69 % after 20 thermal cycles between 1773 K and room temperature, and a mass gain of 1.53 % after 217 h of oxidation at 1773 K. The high fluidity of molten Si facilitated the outer layer's ability to replenish the inner layer, thereby healing defects within the coating. Combined with the viscous flow property of SiO2 during oxidation, the outer layer achieved a dynamic sealing. The coating integrated a liquid-phase-rich compensatory outer layer with a SiC whisker-reinforced crack-resistant inner layer, which worked synergistically to provide effective oxidation protection.