CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Mo Wei,Juan Liu,Bing Liu,Kai Xin Song,Cheng Chao Hu,Yu Hui Huang
Alkaline earth metal fluorides, BaF 2 and SrF 2 , are promising low-permittivity ceramics with excellent microwave dielectric properties. However, achieving ideal densifications in BaF 2 and SrF 2 ceramics remains challenging due to their low surface-free energy. In this study, the sintering characteristics of BaF 2 and SrF 2 ceramics are optimized via forming (1– x )BaF 2 - x SrF 2 ( x = 0.2, 0.4, 0.5, 0.6, and 0.8) solid solution ceramics. X-ray diffraction (XRD) patterns and Raman spectra provide compelling evidence for successfully forming (1– x )BaF 2 - x SrF 2 solid solutions across the entire composition range. The solid-solution effect significantly enhances densification at a much lower sintering temperature of around 825 °C. Notably, 0.6BaF 2 -0.4SrF 2 ceramics exhibit the optimal microwave dielectric properties with a permittivity ( ε r ) of 7.26, quality factors ( Qf ) of 61,006 GHz at 10 GHz and 106,000 GHz at 25 GHz, and a temperature coefficient of resonant frequency ( τ f ) of −97.46 ppm/ ° C. Additionally, the advancement of low-temperature co-fired ceramic (LTCC) technology for high-density electronic packaging presents a significant challenge in achieving compatibility between the coefficient of thermal expansion (CTE) of the packaged components. The 0.6BaF 2 -0.4SrF 2 ceramics exhibit a significantly higher CTE of 21.67 ppm/ ° C compared to most low- ε r ceramics (usually below 10 ppm/ ° C), resulting in better CTE matching with organic laminates and metal electrodes. Therefore, BaF 2 -SrF 2 solid solution ceramics, addressing the need for low- ε r , high- Qf , and high CTE, offer a potential solution for high-reliability LTCC electronics.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Jingpeng Li,Xiao Han,Sisi Yao,Dengkang Guo,Fuxiang Chu
The dimensional instability and flammability issues of wood hinder its application as a structural material in construction. In this study, we integrated wood surface densification technology with a chemical modification strategy to develop flame-retardant, high-strength, and dimensionally stable woods. The modified wood demonstrates a flexural strength of 193.98 MPa, surpassing that of the majority of both inorganic and organic materials. Additionally, after being immersed in water for 24 h, the composite material exhibits a rebound rate of merely 2.62 % and a water absorption rate of 3.16 %. Most significantly, the material's flame retardancy is substantially enhanced after treatment, resulting in negligible combustion when exposed to an open flame. The analyses reveal that surface densification chiefly improves the mechanical properties of wood. The introduction of ammonium dihydrogen phosphate (ADP) into cell walls enhances dimensional stability and flame retardancy, but it comes at the expense of mechanical performance. However, when epoxy polymer is introduced into the cell cavity, it effectively counteracts the adverse impact of ADP, thereby improving both the mechanical properties and dimensional stability of wood. This study effectively addressees the challenges of dimensional instability and flammability inherent in wood as a structural material in construction.
研究领域:
材料科学
·
林业工程
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DOI
高影响因子
FUSION ENGINEERING AND DESIGN
·
2023
·
IF 1.7
Chan Wang,Ping Wang,Qing Yu Hou,Zhi Qiang Cui,Ning Fei Zhang,Lai Ma Luo,Zhen Yi Huang
In the present work, the feasibility and effectiveness of fabricating La 2 O 3 -doped W-based bulk using W-based composite powders of core-shell structure with W particle as a core and La(OH) 3 as a shell, without hydrogen reduction treatment, was evaluated. La(OH) 3 was first coated on the surface of pure W (uncoated) powders at a weight percentage of 3.50% to prepare composite (coated) powders using the electroless plating method. The uncoated and coated powders without being treated by hydrogen reduction were then sintered using spark plasma sintering (SPS) to fabricate bulks. The results showed that the core-shell structure with W particle as a core and La(OH) 3 film as a shell was fabricated. La 2 O 3 -doped W-based bulk with about 2.93 wt.% La 2 O 3 was obtained because of the transformation from La(OH) 3 to La 2 O 3 . The La 2 O 3 particles with larger sizes were distributed mainly at W grain boundaries and those with smaller sizes were distributed mainly inside W grains. The major densification mechanism of the sintered bulk from coated powders was the filling effect of La 2 O 3 particles on the pores as compared with the sintered bulk from uncoated powders, which could be evaluated by using a two-ball sintering neck model. The relative content of O in the form of WO 3 in the sintered bulk from coated powders was identical to that in the sintered bulk from uncoated powders. The W grain size of the sintered bulk from coated powders was smaller than that of the sintered bulk from uncoated powders. The thermal properties, mechanical properties, and irradiation properties of the sintered bulk from coated powders were all higher than those of the sintered bulk from uncoated powders. With the increase of sintering temperature, the evolution of the coated powders in the initial sintering period could be divided into six stages that were not completely independent and occurred in approximate sequence from the perspective of simplification. It was feasible and effective to fabricate La 2 O 3 -doped W-based bulk using the precursor W-based composite powders of core-shell structure with W particle as a core and La(OH) 3 as a shell without being treated by hydrogen reduction.
研究领域:
材料科学
·
冶金工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Fei Zuo,Fan Meng,Dong-Tao Lin,Jun-Jie Yu,Hong-Jian Wang,Shen Xu,Wei-Ming Guo,Carmen Cerecedo,Víctor Valcárcel,Hua-Tay Lin
A novel composite of 12 mol% CeO 2 -stablized tetragonal ZrO 2 reinforced with Al 2 O 3 whiskers (designated as Ce-TZP/A w ) has been prepared and studied in this work. The objective of this investigation was to systematically study the influence of whisker-aspect-ratio on the densification behaviors, microstructure evolution, and mechanical properties of Ce-TZP/A w composite. Results showed that the sintered density of composite increased and the grain growth tended to diminish with the decrease in whisker aspect radio. Both the fracture toughness and flexural strength reached maximum values of 475 ± 12 MPa and 11.4 ± 0.2 MPa m 1/2 , respectively at a whisker aspect ratio of about 12. It was also observed that the fracture toughness, flexural strength and tetragonal to monoclinic ZrO 2 transformation of the dual-phase composite exhibited similar variation trend as a function of the whisker-aspect-ratio, which suggested that the stress-induced phase transformation should be the main toughening and strengthening mechanism in the Ce-TZP/A w composite.
研究领域:
材料科学
·
力学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Bohan Wang,Guofu Xu,Jiwu Huang,Håkan Engqvist,Wei Xia,Le Fu
Effects of dopants with different valences on the densification behavior and phase composition of a ZrO 2 –SiO 2 nanocrystalline glass-ceramic (NCGC) during pressureless sintering were investigated in this study. The raw powder of Ca 2+ , La 3+ , Ce 4+ and Ta 5+ ions doped ZrO 2 –SiO 2 (referred to as Ca-ZS, La-ZS, Ce-ZS, Ta-ZS, respectively) and pure ZrO 2 –SiO 2 (PZS) sample were synthesized by sol-gel method, followed by pressureless sintering. Compared with the PZS sample, doping of Ca 2+ and La 3+ ions significantly promoted the densification of the NCGCs. The “densification promotion” effect was attributed to the formation of oxygen vacancies and the decrease of SiO 2 viscosity due to doping of aliovalent cations. The dopants with various valences showed significant effects on the phase compositions of the NCGCs during sintering. Doping of Ca 2+ ion accelerated the reaction kinetics between ZrO 2 nanocrystallites and amorphous SiO 2 to yield ZrSiO 4 . The La 3+ ion acted as destabilizer of t-ZrO 2 , which resulted in a rapid tetragonal (t) to monoclinic (m) ZrO 2 phase transformation during sintering, while in the Ta 5+ and Ce 4+ ions doped sample, the phase transformation occurred gradually. All the doping ions increased the lattice parameters and the volume of t-ZrO 2 unit cell, while the effects of the doping ions on the lattice parameters of m-ZrO 2 unit cell were more complex.
研究领域:
材料科学
·
无机化学
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产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2022
·
IF 9.879
Hebing Wang,Yiwu Pan,Xiangyu Jin,Can Wu,He Huang,Xiaojie Yan,Changqing Hong,Xinghong Zhang
Fiber-reinforced aerogel composites (FACs) can be applied to the thermal protection system of aerospace vehicles, but the ablative recession is unsatisfactory. We report a novel quartz felt-reinforced phenolic aerogel composite with surface densification (QFPS). The composite with gradients provides enhanced thermal protection under high-temperature and repeated ablation. QFPS was fabricated through surface ceramicizable-resin impregnating and internal phenolic resin aerogel impregnating. QFPS showed desirable thermal and mechanical properties . The internal thermal conductivity was below 0.03 W/(m⋅K), and the tensile, bending, and full-volume rebound compressive strengths were 11.22, 16.25, and 0.48 MPa. Oxy-acetylene ablation test showed a linear setback of 0.003 mm/s, a weight loss of 0.016 g/s for the composite, with a backside temperature below 70 °C. The 10-times repeated butane ablation test showed a slight recession with linear setback and weight loss of 0.30 μm/s and 5.70 mg/s. This composite presents huge application prospects in aerodynamic heating environments.
研究领域:
航空航天材料
·
热防护系统
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2023
·Vol. 16
·期 2
·645-656
·
IF 6.7
Yunjie Lu,Zhaohui Li,Zewei Li,Shihao Zhou,Ning Zhang,Jianming Zhang,Lu Zong
Adhesive hydrogels (AHs) are considered ideal materials for flexible sensors. However, the lack of effective energy dissipation networks and sparse surface polar groups in AHs lead to poor mechanical properties and interfacial adhesion, which limit their practical application. Herein, a tough, long-lasting adhesive and highly conductive nanocomposite hydrogel (PACPH) was fabricated via the synergy of interfacial entanglement and adhesion group densification. PACPH was obtained by the in situ polymerization of highly carboxylated cellulose nanocrystals (SCNCPA, surface pre-grafted polyacrylic acid chains, C–COOH = 11.5 mmol g−1) with the acrylic acid precursor. The unique tacticity of SCNCPA provides strong interface entanglement and multiple hydrogen bonds with the PACPH network, which further increases the energy dissipated during SCNCPA displacements, and enhances the mechanical properties of PACPH (tensile strength = 1.45 MPa, modulus = 332 kPa, and fracture toughness = 13.2 MJ m−3). Meanwhile, SCNCPA increases the density of surface polar groups in PAPCH and also acts as an anchor point to improve the adhesion strength (>2–3 times) of PACPH on various substrates. The combination of excellent mechanical, adhesive, and conductive properties of the PAPCH-integrated patches enables long-term monitoring of human daily activities and electrocardiogram (ECG) signals, verifying that PAPCH is a promising material platform for the further development of flexible sensors and other health management devices.
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DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Meng Cao,Wen Bin Hong,Xiao Dong Yang,Xiao Jian Yan,Lei Li,Shu Ya Wu,Xiao Long Zhang,Xiang Ming Chen
The transportation of Zn 2+ in acetic acid (HOAc) or Zn(OAc) 2 water solution was considered crucial for the successful cold sintering of ZnO ceramics. However, our work shows that ZnO ceramics can even be densified by cold sintering with the aid of solid Zn(OAc) 2 ·2 H 2 O without introducing extra free water. DSC-TG analysis reveals that pure Zn(OAc) 2 ·2 H 2 O is dehydrated completely into solid Zn(OAc) 2 during heating in an open environment, while it melts in ZnO-Zn(OAc) 2 ·2 H 2 O mixture or a high-pressure and semi-closed circumstance due to the strongly suppressed dehydration. Consequently, molten Zn(OAc) 2 ·2 H 2 O acts as the transient liquid medium for the dissolution-precipitation process at over 100 °C, and plays a dominant role in the densification, microstructural evolution , and mechanical robustness of the cold-sintered ZnO ceramics. The densification mechanism is confirmed by the pressure-time curves, and reveals a novel strategy for cold sintering of water-insoluble ceramics by introducing molten hydrated salt or alkali as the transient liquid medium.
研究领域:
材料科学
·
陶瓷
·
烧结技术
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产品关联
DOI
高影响因子
Nanoscale
·
2026
·
IF 5.1
Fanjie Shi,Henghan Dai,Ning He,Yang Guo,Yufan Shen,Huifang Wang,Hai Xu,Yuzhen Wang,Gengzhi Sun
Ti3C2TX MXene with good mechanical strength, metallic conductivity and ultrahigh volumetric capacitance is a promising candidate for developing advanced fibers toward the applications of fibrous supercapacitors (FSCs); however, the weak interlayer interaction, random stacking during coagulation and unsuitable channels for ion transport impose crucial difficulties in continuous spinning strong MXene fibers with desirable charge storage ability. Herein, we propose a coaxial spinning strategy accompanying with spontaneous radial densification for the simultaneous achievements of both improved fiber mechanical strength and charge storage capability. The intercalation of sodium alginate (SA) in core (S/M) expands interlayer spacing and produces suitable paths for ion diffusion, while the presence of SA/graphene oxide (S/G) sheath generates radial compression during dehydration because of capillary force, enhances stress transfer within fiber, and avoid short circuit in FSC. The optimized S/M@S/G fiber exhibits a tensile strength of 238 MPa and a volumetric capacitance of 906 F cm−3 at 1 A cm−3. The assembled FSCs provide a capacitance of 153 F cm−3 together with an energy density of 13.6 mWh cm−3. Notably, owing to the improved mechanical properties, FSCs can be weaved into glove and provide power for an electronic watch.
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2026
·
IF 4.7
Tao Guo,Qiulin Niu,Lu Jing,Tao Zhong,Chenyi Zhu,Binghui Wu,Shengfeng Zhang,Shibo Guo
To improve h-BN dispersion and the local interfacial environment in WC-based cemented carbides, an h-BN@Al₂O₃ composite powder was prepared by heterogeneous nucleation and calcination, with h-BN as the designed core phase and Al₂O₃ as the designed outer-layer component. The composite powder was incorporated into WC-based cemented carbides consolidated by spark plasma sintering (SPS), and the effects of powder content and sintering temperature on phase composition, microstructure, mechanical properties, and densification characteristics were examined. The h-BN@Al₂O₃ content was closely related to WC grain size, microstructural uniformity, and porosity. At 1300 °C, the specimen containing 5 vol% h-BN@Al₂O₃ had a fine, relatively homogeneous microstructure with few visible pores; higher additions increased porosity and local particle agglomeration. For the 5 vol% composition, raising the sintering temperature from 1100 to 1400 °C increased the relative density and reduced visible porosity. At 1500 °C, local WC grain coarsening, microstructural inhomogeneity, and residual porosity increased, accompanied by lower mechanical properties. The best overall performance was obtained with 5 vol% h-BN@Al₂O₃ at 1400 °C: a relative density of 99.1 ± 0.4%, flexural strength of 871.3 ± 26 MPa, Vickers hardness of 1912.1 ± 38 HV, and fracture toughness of 9.86 ± 0.2 MPa·m 1/2 .
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DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2026
·
IF 19.9
Chunbiao Liu,Zhihai Liu,Yu Zhang,Yifan Qin,He Zhang,Jiaxing Gao,Mengyao Zhang,Wei Jin,Tongshuo Zhang,Zhenrui Wang,Xuhao Ji,Wenxuan Gu,Mengqi Chen,Libo Yuan
Biological soft photonics shows broad potential in wearable health monitoring. Hydrogel flexible optical fibers (HFOFs) possess significant application potential due to biocompatibility. However, while high water content and multi-network architectures endow HFOFs with unique biological and mechanical advantages, they also introduce substantial optical losses, thereby limiting their application in meter-scale flexible photonic systems. This study proposes a synergistic strategy combining water-state regulation and network densification. By increasing the fraction of bound water, the absorption loss associated with free water is reduced, while network densification suppresses scattering loss arising from structural heterogeneity. Polyacrylamide hydrogel optical fibers are fabricated using a spider-silk-inspired draw-spinning method. Combined continuous stretching and thermal treatment induce chain alignment, network densification, and the formation of hydrogen-bonded nanoclusters. These structural changes create a confined hydration environment, resulting in a more compact hydrogel fiber network and increasing the bound-water fraction to 70%. The fabricated HFOFs exhibit low optical loss (0.0745 ± 0.0012 dB/cm) and small diameter (120 µm), enabling a tenfold increase in light-guiding distance. The low-loss HFOFs are further integrated into skin-conformal devices, successfully applied in silent speech recognition and braille recognition. This study proposes a general strategy for designing soft photonic materials with low loss and high compliance.
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Zhao Li,Bo Dai,Guixiang Liu,Yong Ren,Fang Xu,Nina Ge
Presintering is commonly used to improve the density and properties of ceramics; however, its prolonged thermal treatment undermines the time- and energy-saving advantages of spark plasma sintering (SPS). This study investigates whether conventional pressureless presintering (CPP) can be omitted or replaced by an integrated spark plasma presintering (SPP) approach in the fabrication of spinel ferrites, and establishes correlations between the presintering method and the resulting densification, phase composition, oxygen vacancy concentration, and magnetic properties. Li 0.5 Fe 2.5 O 4 (LF), NiFe 2 O 4 (NF), Li 0.4 Zn 0.2 Fe 2.4 O 4 (LZF), and Ni 0.4 Zn 0.6 Fe 2 O 4 (NZF) were prepared via two routes: CPP followed by SPS, and SPP followed by SPS. For LZF and NZF, SPP led to higher final density and microhardness (∼4.9 g cm −3 , ∼1000 HV 1 ), whereas LF and NF showed lower densification due to insufficient activation (<4.5 g cm −3 , <900 HV 1 ). X-ray photoelectron spectroscopy (XPS) revealed that SPP reduced the Fe 2+ /Fe 3+ ratio relative to CPP, owing to the low oxygen partial pressure and short dwell time that suppress lithium loss and oxygen vacancy formation. Raman spectroscopy confirmed lower α-Fe 2 O 3 retention in the conventionally presintered (CPP-ed) samples. Saturation magnetization ( M s ) was consistently higher for the spark plasma presintered (SPP-ed) samples, with increases of more than 10%. This enhancement is attributed to the lower Fe 2+ content, reduced porosity, and minimal carbon contamination in the SPS-ed samples. These findings demonstrate that CPP can be successfully replaced by SPP stage for Zn-doped spinel ferrites, offering a simplified processing route with comparable or improved magnetic and mechanical properties. For non-Zn compositions, further optimization of SPP parameters is required to achieve equivalent performance.
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DOI
高影响因子
危险品化学品经营许可证（带存储）