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Isothermal annealing comprehensively improving the magnetic properties of nanocrystalline PrCo5 magnets

Journal of Alloys and Compounds 2025年 1028卷

作者： Li, Yuqing Pan, Xiaowen Bian, Mengying Zhang, Dongtao Liu, Wenhe Liu, Lin Song, Wenna Liu, Weiqiang Xia, Weixing Yue, Ming State Key Laboratory of Materials Low-Carbon Recycling Beijing University of Technology Beijing100124 China College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials Ministry of Education of China Beijing University of Technology Beijing100124 China Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Material Technology and Engineering Chinese Academy of Sciences Ningbo315201 China

We demonstrate the development of nanocrystalline PrCo5 magnets through a modified hot-deformation process incorporating Pr-rich composition. This approach effectively suppresses the formation of the detrimental Pr2Co17 phase, yet introduces the Pr5Co19 phase, which results in magnetic properties comparable to the previous reports. Subsequent isothermal annealing treatment significantly reduces the Pr5Co19 content, optimizes texture, and minimizes strain concentration at stacking fault positions. This comprehensive microstructural refinement results in the simultaneous enhancement of magnetic properties. The optimized magnets exhibit superior performance metrics with remanence (Mr) of 9.72 kG, coercivity (Hci) of 10.12 kOe, and maximum energy product (BH)max of 22.34 MGOe, representing increases of 14 %, 20 %, and 60 % respectively compared to the as-deformed state. The squareness of the demagnetization curve shows marked improvement as well. Our findings establish an effective pathway for optimizing magnetic properties in nanocrystalline permanent magnet materials. © 2025 Elsevier B.V.

关键词： Permanent magnets

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Imaging the atomic configuration of defects in laves phase MgNi2 using 4D-STEM

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Scripta Materialia 2025年 265卷

作者： Li, Jiaxin Zhang, Min Zhang, Chunchen Han, Jiuhui Tianjin Key Laboratory of Advanced Functional Porous Materials Institute for New Energy Materials and Low-Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology Tianjin300384 China School of Chemistry and Chemical Engineering Tianjin University of Technology Tianjin 300384 China

Laves phases are promising candidates for high-temperature structural materials, with their mechanical properties strongly influenced by defect structures. In this study, the atomic configurations of defects in the Laves phase MgNi2 were systematically investigated using four-dimensional scanning transmission electron microscopy (4D-STEM). Combined multislice simulations and experimental results validated the robustness of Center-of-Mass (CoM) imaging based on 4D-STEM for simultaneously resolving both heavy and light elements in MgNi2 under varying sample and instrument parameters. We conducted a detailed analysis of planar faults and dislocations in MgNi2 using 4D-STEM. Our findings revealed that the hexagonal planar faults, formed via relative sliding of adjacent regions, are characterized by nickel deficiency. Additionally, the atomic structure of dislocations in regions containing non-basal stacking faults suggests a synchroshear deformation mechanism. These results demonstrate the effectiveness of 4D-STEM in probing complex defect structures in intermetallic materials, offering critical insights into their deformation behavior. © 2025 Acta Materialia Inc.

关键词： Crystal atomic structure

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Integrated Design of Polysulfide Shuttling and Lithium Dendrite Suppressing Framework: In2o3-In2s3 Embedded Carbon Cloth for Lithium-Sulfur Full Batteries

SSRN

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SSRN 2025年

作者： Li, Junting Li, Wenjiang Tian, Yuan Wang, Cheng Institute for New Energy Materials and Low-Carbon Technologies Tianjin Key Laboratory of Advanced Functional Porous Materials School of Materials Science and Engineering Tianjin University of Technology Tianjin300384 China School of Materials Science and Engineering Tianjin University of Technology Tianjin300384 China

The formidable polysulfide shuttling in conjunction with sluggish sulfur redox kinetics on the sulfur cathode and unlimited lithium dendrite growth on the anode severely impede their popularization of lithium-sulfur (Li-S) batteries. Here, the In2O3-In2S3 heterogeneous nanosheets in-situ grown on carbon cloth (In2O3-In2S3@CC) is synthesized by a simple hydrothermal method, which is simultaneously served as an efficient sulfphilic and lithiophilic host to enable stable cycling and boost high-performance Li-S full batteries. Concretely, one side of loading sulfur with In2O3-In2S3@CC acts as S/In2O3-In2S3@CC cathode to strengthen chemical anchoring and propel redox reaction kinetics, while the other side via electrochemical deposition of lithium uses as In2O3-In2S3@CC/Li anode to induce uniform Li deposition. Moreover, the three-dimensional carbon network framework is endowed with long-range effective electron/ion channels, sufficient storage space for sulfur physically confining and homogeneous Li distribution, as well as alleviating the volume change of electrode. As a result, the flexible self-standing dual-functional In2O3-In2S3@CC host significantly suppresses polysulfide shuttling and mitigates lithium dendrite growth, as revealed by theoretical simulations. The assembled Li-S full battery (S/In2O3-In2S3@CC||In2O3-In2S3@CC/Li) exhibits a high discharge capacity of 832.6 mAh g-1 at 1 C with a minimum capacity fading rate of 0.065% per cycle and superb rate capability up to 5 C under sulfur loading of 3 mg cm-2. This work offers insight into the practical application for modified carbon cloth towards advanced energy storage and conversion fields. © 2025, The Authors. All rights reserved.

关键词： Redox reactions

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3D printing of (Cf-Csf)/ZrB2-SiC composites through coextrusion of flexible pre-infiltrated Cf/ZrB2 fiber bundle and Csf/ZrB2 paste

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Ceramics International 2025年

作者： Zhang, Yixin Cheng, Yehong Fang, Jinming Ma, Denghao Sun, Xin Li, Junping An, Yumin Hu, Ning Zhao, Libin School of Mechanical Engineering Hebei University of Technology Tianjin300401 China Ministry of Education Tianjin300401 China Key Laboratory of Hebei Province on Scale-span Intelligent Equipment Technology Tianjin300401 China Chongqing Science Innovation Center Hebei University of Technology Chongqing401135 China Science and Technology of Advanced Functional Composite Materials Laboratory Aerospace Research Institute of Materials and Processing Technology Beijing100076 China State Key Laboratory of Reliability and Intelligence Electrical Equipment Hebei University of Technology Tianjin300401 China

This work addresses two major challenges in 3D printed ceramic composites: inadequate ceramic matrix infiltration in fiber bundles and the lack of optimized fiber-matrix interfaces. We developed a breakthrough fabrication strategy featuring: A tailored flexible carbon coating specifically designed for 3D printing applications, deposited on carbon fibers to create a suitable interface;A specialized pre-infiltration method enabling uniform ceramic slurry distribution in continuous carbon fiber bundles;and A unique co-extrusion process combining flexible pre-infiltrated Cf/ZrB2 bundles with Csf/ZrB2 paste. The resulting (Cf-Csf)/ZrB2-SiC composites, fabricated through multi-cycle precursor infiltration-pyrolysis, demonstrate remarkable mechanical properties (flexural strength: 237.6 MPa;fracture toughness: 7.30 MPa m1/2) and exceptional ablation resistance (enduring 2190 °C surface temperatures for 1320 s in wind tunnel testing). This work establishes a new paradigm for manufacturing ultra-high temperature ceramic composites with simultaneously enhanced mechanical and thermal performance. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Fracture toughness

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Lightweight Y2O3 stabilized ZrO2 (YSZ) fiber porous ceramics with ultra-low thermal conductivity

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Ceramics International 2025年

作者： Zhao, Yingjie Sun, Xiaohong Guo, Ruisong Liu, Hongyao Zhao, Xinqi Huo, Mingda Ren, Junbo Fu, Weijie Li, Xin School of Materials Science and Engineering State Key Laboratory of Precious Metal Functional Materials Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University Tianjin 300072 China School of Materials Science and Engineering State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an710049 China School of Materials Science and Engineering Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province Hangzhou Innovation Institute of Beihang University Hangzhou310052 China

Fiber porous ceramics have numerous applications in protecting structural parts from melting due to combustion gases in aircraft engines. Although these materials have been utilized for decades, considerable research continues to focus on their further optimization, particularly in enhancing high-temperature resistance, lowering thermal conductivity, and improving compressive strength. In this work, the three-dimensional Y2O3-stabilized ZrO2 (YSZ) fiber porous ceramics were fabricated by adding silica-boron sol (SBS) as an inorganic binder to the YSZ fiber substrate followed by a pressureless sintering process. During this process, a borosilicate glass phase was developed at the intersections of the fibers, helping enhance the thermal stability and improve mechanical properties. The three-dimensional YSZ fiber porous ceramics were characterized by ultra-low thermal conductivity (0.054–0.065 W·m−1·K−1), enhanced compressive strength (144.82–238.81 kPa), high open porosity (88.64–91.67 %) and extremely low bulk density (0.41–0.53 g·cm−3). When the SBS content in the YSZ fiber porous ceramics was 25 wt%, the sample achieved optimal overall performance, with a low bulk density of 0.44 g·cm−3, thermal conductivity of 0.058 W·m−1·K−1 and the compressive strength of 201.26 kPa. The research provides critical insights for preparation and engineering applications of YSZ fiber porous ceramics in aircraft engine thermal protection systems. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Binders

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Remarkable energy storage performances in tungsten bronze Sr2Ag0.2Na0.8Nb5O15-based ceramics through relaxor tuning

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Chemical Engineering Journal 2025年 513卷

作者： Han, Mingzhe Wang, Yan Tong, Yihan Feng, Zhiwei Chao, Xiaolian Yang, Zupei Yang, Bian Wei, Lingling Key Laboratory for Macromolecular Science of Shaanxi Province School of Chemistry and Chemical Engineering Shaanxi Normal University Shaanxi Xi'an710062 China Shaanxi Engineering Laboratory for Advanced Energy Technology School of Materials Science and Engineering Shaanxi Normal University Shaanxi Xi'an710062 China School of Materials Science and Engineering Xi'an University of Technology Engineering Research Center of Conducting Materials and Composite Technology Ministry of Education Shaanxi Engineering Research Center of Metal-Based Heterogeneous Materials and Advanced Manufacturing Technology Shaanxi Province Key Laboratory for Electrical Materials and Infiltration Technology Shaanxi Xi'an710048 China

The immense potential of dielectric energy storage capacitors for high-power pulse device, especially the tetragonal tungsten bronze compounds, has spurred significant recent research and development. However, balancing the inverse correlation between polarization and electric breakdown field remains a challenging task for satisfactory energy storage performances. Here, we propose a feasible strategy of coupling ferroelectric polarization and relaxor behavior by incorporating non-equivalent cations Ho3+ and Ti4+ into Sr2Na0.8Ag0.2Nb5O15 matrix to enhance energy storage performances. Owing to the non-equivalent cation Ho3+ and Ti4+ incorporated into Sr2Na0.8Ag0.2Nb5O15 matrix for Sr2+ and Nb5+, as-obtained crystallographic structure evolved from orthorhombic to tetragonal phase and experienced a shrinkage in the volume of unit cell, which further induced the formation of polar nanoregions and the enhanced relaxor behavior as verified by TEM results and dielectric spectrum. Besides the ferroelectric to paraelectric transition at Tc, another low-temperature anomalous dielectric peak could also be observed, and two independent dielectric peaks merged into a broadened peak at higher contents substitution of Ho3+/Ti4+. The evolution of the above structure and the enhanced relaxor characteristics significantly increased maximum polarization (Pmax) and reduced remanent polarization (Pr). Benefited from the effective inhibition of abnormal grain growth by Ho3+and Ti4+, all samples presented an equiaxed grain with reduced grain size and uniformity in size distribution, as well as significantly suppressed leakage current confirmed by complex impedance results, all contributing to a remarkable improvement in breakdown electric field (Eb). As a result, Sr1.80Ho0.20Na0.8Ag0.2Nb4.80Ti0.20O15 sample exhibited an optimum recoverable energy storage density (Wrec) of 5.8J/cm3 and energy storage efficiency (ƞ) of 91.2 %, with excellent performance across different frequencies and fatig

关键词： Grain growth

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Self-Adaptive Reflectance Film for Passive Temperature Regulation in Diverse Environments

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advanced science 2025年

作者： Yang, Shuo Tang, Sizhe Cai, Yufeng Ye, Zhiming Zou, Xiangbin Yuan, Xueyu Song, Yujie Li, Bing Tang, Dongyan Liu, Ming School of Chemistry and Chemical Engineering Harbin Institute of Technology Harbin150001 China State Key Laboratory of Special Functional Waterproof Materials Beijing Oriental Yuhong Waterproof Technology Co. Ltd Beijing101111 China Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences Ningbo315201 China Advanced Energy Science and Technology Guangdong Laboratory Huizhou516000 China State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin150001 China

Passive thermal-regulation strategies have become increasingly important due to the strain alleviated on power grids for temperature management. Designing a system capable of automatically switching between cooling and heating modes in response to changing ambient conditions presents several specific challenges that engineers and researchers are actively addressing. In this research, a CaCl2 incorporated PNIPAM coated fluorinated poly(aryl ether) (FPAE) porous film with tunable reflectance is developed. The aim is to mitigate the reliance on active cooling systems, which consume significant amounts of energy. The moisture-temperature dual sensitive film exhibits a tunable reflectance range between 91.1% and 39.1% via phase change of the PNIPAM layer. Coupled with an infrared emissivity of 96.0%, a daytime cooling of 10 °C compared to the control experiment is achieved. Coating the film with a photothermal layer results in an adaptive Janus film that is capable of autonomous switching between heating and cooling, and demonstrates a heating of 22.5 °C in a cold environment. The facile preparation method, excellent cyclic stability, mechanical properties, and UL-94 V-0 rating enable promising applications of the smart film under diverse living environments. © 2025 The Author(s). advanced science published by Wiley-VCH GmbH.

关键词： Self tuning control systems

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Multispectral‐Responsive MXene Nanolayer Energy‐Saving Windows for High‐Absorption Electromagnetic Interference Shielding

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Nano Energy 2025年 141卷

作者： Jin, Meng Zhou, Xinfeng Qi, Cheng-Zhang He, Ping Ye, Lvxuan Min, Peng Yu, Zhong-Zhen Zhang, Hao-Bin State Key Laboratory of Organic-Inorganic Composites College of Materials Science and Engineering Beijing University of Chemical Technology Beijing100029 China Beijing Key Laboratory of Advanced Functional Polymer Composites Beijing University of Chemical Technology Beijing100029 China

Traditional glass windows, as channels for light, information, and heat exchange, are potential breaches for electromagnetic radiation and temperature regulation. However, materials simultaneously possessing both transparent, high-absorption electromagnetic interference (EMI) shielding and thermal management performances remain scarce. The narrow-band and unstable spectral responses of available transparent materials are the fundamental obstacles. To address these issues, we theoretically unveil the visible opacity (6.9 %/monolayer), high near-infrared transmittance (>80 %) of the Ti3C2Tx MXene nanolayer, and its stable ultra-wideband spectral response across the long-wave infrared, terahertz, and microwave regions. The unique optical characteristics make it possible to regulate multispectral radiation by constructing a radiative regulation (RR) window. Significantly, perfect electromagnetic absorption (≥99 %) and high average absorption (>90 %) are realized for RR windows with excellent EMI shielding and transparency, and the effective absorption region is tunable in the GHz-THz region. Meanwhile, the radiation-transparent MXene nanolayer and infrared-emissive design in the RR window help realize radiative cooling function to avoid heat accumulation, giving an energy-saving performance of 302.4 MJ m−2. This work will open the way to developing a new generation of cross-band technologies for multispectral manipulation. © 2025

关键词： Electromagnetic pulse

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Enhancing the mechanical and tribological properties of Mo-Cu composites via three-dimensional hierarchical micro/nano heterostructures induced by Al doping

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Journal of Alloys and Compounds 2025年 1021卷

作者： Zhuang, Zehang Li, Zongbo Long, Xiao Feng, Yan Wang, Richu Peng, Xiang Cai, Zhiyong School of Materials Science and Engineering Central South University Changsha410083 China National Key Laboratory of Science and Technology on High-strength Structural Materials Central South University Changsha410083 China Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province Central South University Changsha410083 China

While heterogeneous materials leverage synergistic interactions between distinct phases to overcome property trade-offs in homogeneous systems, controlling multiscale phase distribution and interfacial stability remains a critical challenge for achieving optimal performance. In this study, we address this fundamental issue through Al-doped hierarchical design, fabricating a novel Mo-Cu composite with three-dimensional (3D) multiscale heterogeneity. The microstructure, formation mechanisms, tribological behavior, and mechanical properties of the composite were systematically investigated. The Al-doped Mo-Cu composite exhibited distinctive structural characteristics, including: (1) a spatial network formed by micron-sized Mo phases within the Cu matrix;(2) submicron-sized Mo phases predominantly surrounding the micron-sized Mo phases, with some dispersed in the Cu matrix;(3) nanoscale Mo and Cu phases embedded in the Mo matrix;and (4) Al-rich nanoparticles distributed within Mo nanograins, at grain boundaries, and along Mo/Cu interfaces. First-principles calculations revealed that Al doping significantly reduces the formation energy and interfacial energy of the Mo-Cu system, mitigating phase separation and enhancing interfacial stability and bonding strength. The electron localization function (ELF) and partial density of states (PDOS) analysis further confirmed the formation of covalent bonds at Al-doped Mo/Cu and Mo/bcc Al interfaces, providing a theoretical basis for the observed microstructural features and outstanding properties. Compared to undoped composites, the Al-doped Mo-Cu composite exhibited a 9.1 % reduction in the average friction coefficient, along with substantial decreases in wear depth (2.6 %), wear width (14.4 %), and wear volume (23.4 %). Additionally, its hardness (525 HV), compressive strength (1795 MPa), and fracture compressive strain (10.3 %) increased by 24.4 %, 112.0 %, and 72.9 %, respectively, setting new performance benchmarks among sin

关键词： Compressive strength

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Switching Two-Dimensional Sliding Ferroelectrics by Mechanical Bending

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Physical Review Letters 2025年第7期134卷 076101-076101页

作者： Ri He Hua Wang Fenglin Deng Yuxiang Gao Bingwen Zhang Yubai Shi Run-Wei Li Zhicheng Zhong Key Laboratory of Magnetic Materials Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing 100049 China Center for Quantum Matter School of Physics Zhejiang University Hangzhou 310058 China Suzhou Institute for Advanced Research University of Science and Technology of China Suzhou 215123 China Fujian Key Laboratory of Functional Marine Sensing Materials Center for Advanced Marine Materials and Smart Sensors College of Material and Chemical Engineering Minjiang University Fuzhou 350108 China School of Future Technology University of Chinese Academy of Sciences Beijing 100049 China School of Artificial Intelligence and Data Science University of Science and Technology of China Suzhou 215123 China

Two-dimensional van der Waals materials, possessing a unique stacking degree of freedom, offer an alternative strategy for modulating their properties through interlayer sliding. Controlling the stacking order is crucial for tuning material properties and developing slidetronics-based devices. Here, using machine-learning potentials, we propose a mechanical bending approach to manipulate stacking orders and related properties in sliding ferroelectric h-BN, 3R-MoS2, and nonferroelectric bilayer graphene. Our simulations predict the formation of irreversible kinks in bent bilayers, deviating from the expected arclike deformation. This kink formation arises from the interplay between bending energy and interlayer stacking energy. Notably, the bending-induced kink contains a ferroelectric topological domain wall that reverses the polarization of sliding ferroelectrics, a mechanism distinct from the conventional flexoelectric effect. This work proposes an exciting mechanical bending approach to dynamically manipulate the stacking order and associated optical, topological, ferroelectric, and magnetic properties in van der Waals layered materials.

关键词： Van der Waals forces

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