JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2025
·
IF 3.5
Hongbo Wang,Kun Wang,Deren Yang,Xuegong Yu
Fused silica (SiO 2 ) glass is integral to numerous industries owing to its exceptional physical and chemical attributes. Although the hydrolysis of silicon tetrachloride (SiCl 4 ) provides a cost-effective and straightforward route for SiO 2 production, its influence on sintering densification and the underlying mechanisms remains poorly understood. Here, amorphous SiO 2 is prepared by hydrolyzing liquid SiCl 4 at different molar ratios of SiCl 4 to water ( R (SiCl 4 /H 2 O)). As the concentration of H 2 O increases, the SiO 2 specific surface area increases, and the microstructure evolves from agglomerated blocks into a connected skeleton. Sintering these hydrolyzed green samples significantly enhances their bulk density, reaching a maximum of 1.591 g/cm 3 at R = 1:70. Further analysis of the sintering activation energy reveals that this ratio also yields the lowest activation energy (34.439 kJ/mol), pinpointing the optimal conditions for achieving dense amorphous SiO 2 . Additionally, the influence of different microstructures on sintering densification is clarified.
研究领域:
材料科学
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化学工程
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 2
·1-10
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IF 2.8
Cao Xuefeng,Chen Deqin,Li Fengrong,Liu Laijun,Shen Qinghua,Li Chunchun
A series of low-permittivity LiAl 1 − x B x O 2 (0.01 ≤ x ≤ 0.10) ceramics were fabricated by a conventional solid-state reaction method and were characterized for their phase evolution, crystal structure, and dielectric properties. Single-phase LiAl 1 − x B x O 2 solid solutions were formed at a limited compositional range ( x = 0.05) while the secondary phase Li 2 (BAlO 4 ) companied at higher dopant contents. Boron substitution facilitated the sintering behavior and optimized the densification of LiAlO 2 , resulting in dense microstructures and improved dielectric properties. A composition with x = 0.075 exhibited a high quality factor ( Q×f ) of 40,288 GHz along with a low relative permittivity ( ε r ) of 6.3 and a temperature coefficient of resonance frequency (τ f ) of – 191 ppm/ o C. All results indicate that the LiAl 1 − x B x O 2 ceramics can be a promising candidate material in the application of the substrate.
研究领域:
材料科学
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陶瓷工程
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·Vol. 109
·期 1
·e70477
·
IF 3.8
Xu Shen,Yu Zhang,Tianyuan Jiang,Feiyan Cai,Li Tian,Jinshan Yang,Shaoming Dong
Dense nano-infiltration and transient eutectic phase (NITE)-SiC f /SiC composites are prepared through low-temperature sintering technology at 1650°C. The densification of SiC matrix, as well as effects of BN interphase thickness and fiber volume fraction on the morphology and mechanical properties of SiC f /SiC composites are investigated. AlN‒Y 2 O 3 ‒SiO 2 can fully wet SiC at 1650°C and the matrix of SiC f /SiC composites can be densified via 40 wt% sintering aids. A thick BN interphase layer can reduce stress on the fiber and the interphase in stress concentration regions, but may exacerbate stress concentration in non-concentrated regions. A moderate fiber volume fraction is necessary to balance the content and damage of reinforcement to obtain SiC f /SiC composites with high mechanical property. The optimum volume density, open porosity, and flexural strength of SiC f /SiC composites is 2.98 ± 0.05 g/cm 3 , 3.5 ± 1.7%, and 430 ± 34.2 MPa. This work can provide conduction for fabrication and optimization of low-temperature sintering NITE-SiC f /SiC composites.
研究领域:
材料科学
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陶瓷基复合材料
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复合材料加工
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高温材料
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2026
·Vol. 109
·期 1
·e70520
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IF 3.8
Yiran Lin,Le Lu,Zhaofeng Chen,Lixia Yang,Zhiyuan Ma,Xue Feng,Yucheng Guo,Ao Liu,Kai Shen,Yuming Xing,Shuangquan Guo,Xingpu Wang,Junling Liu
SiC fiber-reinforced SiC ceramic matrix composites (SiC f /SiC CMCs) are promising for aero-engine hot-end components due to their excellent high-temperature strength and corrosion resistance. However, they are prone to damage during service, highlighting the need for efficient, low-cost repair technologies. This study proposes a gelcasting repair method for SiC f /SiC composites. By optimizing bimodal SiC powder distribution and employing a N,N-dimethylacrylamide (DMAA)-based gel system, a repair slurry with high fluidity and strong gel-curing ability was developed. This slurry effectively infiltrated pores at the fiber/matrix interface and within fiber bundles. Subsequent silicon infiltration produced β-SiC through reaction with residual carbon, strengthening interfacial bonding. Postrepair characterization showed porosity reduction from 38.01% to 0.85% and density increase from 1.46 to 2.61 g/cm 3 . Flexural strength improved from 29.51 to 125.33 MPa, a 324.7% enhancement. After oxidation at 1200°C for 2 h, the repaired composite retained 91.4% of its original flexural strength. This technique provides a rapid, low-cost pathway for repairing CMCs in aero-engine applications.
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高影响因子
SCRIPTA MATERIALIA
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2019
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IF 4.539
Nan Lu,Gang He,Zengchao Yang,Yong Li,Jiangtao Li
MgO/Graphene composites were prepared by combustion synthesis (CS) followed with spark plasma sintering (SPS) using LiF as sintering additive. The densification mechanism of MgO/Graphene composites doped with LiF was systematically investigated. With incorporating small amount of graphene into MgO , the spectral absorptivity of the composite was improved, whereas the density, hardness and average grain size were decreased. The densification of submicron sized MgO/Graphene ceramics was realized by the balance between sintering promoted by LiF and grain refinement of graphene.
研究领域:
材料科学
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陶瓷工程
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DOI
高影响因子
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2016
·
IF 2.357
Jianhua Zhu,Chenxin Ouyang,Shumin Xiao,Yongyi Gao
This work reports the recent study on the microwave sintering (MS) versus conventional sintering (CS) of NiCuZn ferrites, with particular interests in the densification evolution. NiCuZn ferrite powders were synthesized through the solid state reaction route . Densification behaviors of ferrite samples under the two types of thermal sources were monitored in real-time. Meanwhile, the influences of additives (1 wt% BSZ glass or 1 wt% Bi 2 O 3 ) on the densifications were also investigated. Both constant heating rate (CHR) and master sintering curve (MSC) models were used to evaluate the sintering activation energy ( Q ). Results demonstrated that the microwave-enhanced diffusion mainly occurs at the intermediate sintering stage. The Q -value estimated by MSC method agreed well with that from CHR method. With the influence of microwave electromagnetic field, the activation energy of NiCuZn ferrites was decreased by roughly 100–150 kJ/mol. In addition, doping a small amount of additives could improve densification degree and reduce the minimal energy to activate diffusion mechanisms .
研究领域:
材料科学
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陶瓷学
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烧结技术
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材料电磁处理
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2026
·Vol. 109
·期 8
·e71158
·
IF 4.2
Xu Shen,Tianyuan Jiang,Feiyan Cai,Li Tian,Jinshan Yang,Shaoming Dong
A novel Pr 3 Si 2 C 2 additive was introduced to lower the sintering temperature of NITE-SiC f /SiC composites to 1550°C–1650°C. Pr 3 Si 2 C 2 effectively promoted densification, achieving 3.11 g/cm 3 density and 4.9% open porosity at 1600°C. However, the densification process causes severe thermochemical damage to the interphase layers and fibers. At 1550°C–1600°C, a kinetically-dominated “transient Pr-rich layer” is formed at the fiber/interphase boundary. This stems from a three-order-of-magnitude disparity in Pr-ion diffusion coefficients between the BN interphase and SiC fiber (At 1550°C, D BN ≈ 9.66 × 10 −13 m 2 /s vs. D SiC ≈ 8.31 × 10 −16 m 2 /s). Above 1650°C, Pr 3 Si 2 C 2 decomposition products react with the BN to form SiC, Pr 25 B 14 C 26 , and Pr 6 O 11 , shifting interfacial bonding from weak (23 MPa) to strong (154 MPa). Concomitantly, the Pr-bearing liquid phase infiltrates fibers along grain boundaries, inducing abnormal grain growth (from 8.8 to 54 nm) via Ostwald ripening. This caused monofilament tensile strength to drop from 2771.5 to 624.6 MPa and the Weibull modulus from 6.11 to 3.65. Combined interfacial degradation and fiber lead to a decline in composite performance, with the fracture mode shifting from pseudoplastic to brittle. This study elucidates the corrosion mechanisms of Pr 3 Si 2 C 2 on SiC fibers and BN interphases, providing a crucial theoretical foundation for optimizing the processing window of NITE-SiC f /SiC composites.
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高影响因子
Nature Communications
·
2026
·
IF 18.1
Wang Sen,Tang Senxuan,Fu Tianqi,Jiang Yirong,Lin Yun,Fu Lianlian,Wu Ronghui,Lin Youhui
Natural structural tissues achieve exceptional performance through precisely aligned hierarchical architectures that extend across multiple length scales. However, realizing such multiscale long-range alignment in synthetic bulk hydrogels remains challenging because of the difficulty in constructing a uniformly dense and highly oriented structure that extends throughout the full bulk matrix. Here, we introduce a scalable and versatile Layer-by-Layer Shear Densification (LBSD) strategy that integrates flocculation-induced aggregation with shear-driven progressive alignment, precisely driving the architectural evolution toward compact and uniformly ordered lamellar structures across multiscales. The resulting poly(vinyl alcohol) (PVA) hydrogels with a hierarchical network exhibit a Herman’s orientation factor of 0.91, surpassing previously reported values for bulk hydrogels. The structural orientation enables the hydrogel to exhibit excellent mechanical properties, including a tensile strength of 41.29 ± 2.10 MPa and toughness of 159.37 ± 28.15 MJ·m⁻³. To demonstrate the versatility, this strategy is further used to fabricate gelatin hydrogels, resulting in a 32-fold enhancement in toughness. Anisotropic thermal conductivity, another representative physical property originating from molecular-level alignment, is also demonstrated. This work establishes a generalizable technology for developing high-performance bulk polymeric materials through molecular-level engineering, offering substantial potential for applications in load-bearing components, bioelectronic devices, thermal management systems, etc.
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DOI
PubMed
高影响因子
ADVANCED MATERIALS
·
2026
·
IF 29.1
Bingjie Lou,Xingyue Sun,Haiyi Liang
Polymer gels, such as hydrogel and organogel, are widely used in tissue engineering, biomedicine, and flexible electronic devices due to their good compatibility and environmental stability. However, it is still a great challenge to achieve simultaneous high strength, toughness, and elongation to meet the demands of different applications. Herein, this work proposes a strategy involving freeze-thawing, stretch-drying and thermal annealing in glycerol to fabricate ultrastrong and tough polyvinyl alcohol (PVA) organogel with anisotropic microstructure. Freeze-thawing cycles push PVA chains together through the formation of ice crystals, facilitating the entanglement of polymer chains and the formation of hydrogen bond network. Directional stretch-drying process induces molecular chain orientation and enhances the intermolecular interactions. Thermal annealing (TA) in glycerol promotes chain rearrangement and densifies the cross-linking of hydrogen bond network, which synergistically enhances strength and toughness. The prepared anisotropic PVA organogel exhibits extraordinary toughness of 416 M J / m 3 MJ / m 3 $\mathrm{MJ/m^3}$ , excellent strength of 61.14 MPa, and fracture strain of 961%. Simultaneously, the organogel has high optical transparency ( ∼ 9 0 % ∼ 90 % $\sim 90\%$ ) and superior stability in sub-zero conditions. This work provides a novel and effective strategy for fabricating ultrastrong and tough organogel, offering promising potential applications in bionic tendons for soft robotics and transparent protective shields.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2026
·
IF 6.6
Liu Ningna,Kun Liu,Cui Jingxuan,Feng Aihu,Yun Yu
Functional-group coordination and lamellar structure determine the stability of MXene. • Strong Ti-S bonding passivates active Ti sites and suppresses oxidation. • Functional-group synergy induces ordered and compact MXene lamellae. • Infrared emissivity remains 0.18 after three humid-heat cycles. MXene exhibits intrinsically low infrared (IR) emissivity, making it a promising candidate for IR stealth applications. However, its pronounced oxidation susceptibility constrains long-term stability. Herein, serine (Ser) and glutathione (GSH) were employed to elucidate how functional-group modification regulates active-site passivation and structural densification in MXene films. The coordination affinity of functional groups toward reactive Ti sites plays a key role in environmental stability, with thiol (−SH) moieties preferentially forming strong coordination bonds to passivate active sites, thereby suppressing oxidative degradation. Simultaneously, the synergistic interplay of multiple functional groups promotes nanosheet alignment and structural compaction, effectively hindering oxygen and water penetration. Benefiting from the synergistic effects of active-site passivation and structural densification, the modified MXene film retains low IR emissivity (∼0.18) after three consecutive 24 h humid-heat aging cycles, whereas the emissivity of pristine MXene increases to ∼ 0.34 under the same conditions. This study presents a rational design framework for durable, low-emissivity MXene materials. Download: Download high-res image (199KB) Download: Download full-size image
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Discover Nano
·
2025
·Vol. 20
·期 1
·1-17
·
IF 4.5
Li Jigang,Zhao Panchao,Yi Wei
This work shows a detailed investigation on the purification and densification of Ir target from Ir sponge by hydrometallurgy (exchange resin + extraction + chemical precipitation) combined with powder metallurgy (spray drying + pyrolysis + hot press sintering). The detailed influences of refining techniques on each impurity element and content in the Ir purified system are investigated. The controlling mechanisms of Ir particles in spray drying-pyrolysis processing are studied. The densified evolution of Ir particles during hot press sintering is revealed. After the purified treatment, high-purity Ir precursor [(NH 4 ) 2 IrCl 6 ] was achieved. The synthesized Ir particles are spherical, and the average size is about 5 μm. The purity and density of as-sintered Ir target was 99.999 wt% and 99.16%, respectively. This technological integration broke through the limitations of traditional single methods, creating a new path for the preparation of iridium powder. Moreover, atomization drying technology was applied to this research for the first time. The synergy of these technologies significantly improved the preparation efficiency and the stability of product quality. The prepared products could be used as high–reliability contact and electrode materials in the electronic information field, enhancing the performance and service life of equipment. It should be noted that the purified and densified technologies could be used to synthesize other targets of high-purity and high-density requirements.
研究领域:
冶金学
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材料科学
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无机化学
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化学工程
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电子工程
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DOI
PubMed
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Yiming Yu,Yaowu Wei,Kui Liu,Bo Chen,Junfeng Chen
This paper aims to improve the density and thermal shock resistance of Y 2 O 3 ceramics for the preparation of ultra-pure high-temperature alloy crucible materials. The doping effect of MgF 2 content on the densification behavior, physical properties, and thermal shock resistance of Y 2 O 3 ceramics was systematically investigated in this paper. The results suggested that the presence of MgF 2 greatly promoted the growth of Y 2 O 3 grains and the transformation of the pore structure by liquid-phase sintering. And the mechanical properties of the MgF 2 -doped Y 2 O 3 ceramics were significantly improved. Besides, the marked improvement in the thermal shock resistance of MgF 2 -doped Y 2 O 3 ceramics was attributed to the synergistic action resulting from the growth of grain size and the enhancement of the crack deflection effect. In particular, the relative density of Y 2 O 3 ceramics doped with 1.5 wt% MgF 2 reached 96.4% and the residual flexural strength ratio after thermal shock achieved 45.0%, showing an excellent application prospect.
研究领域:
材料科学
·
陶瓷工程
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高影响因子
危险品化学品经营许可证（带存储）