INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Zhuang Lu,Limeng Liu,Zhaoping Hou,Biao Zhang,Guihong Geng,Yujin Wang,Feng Ye
TaC-Al 2 O 3 composites were prepared by hot pressing. Influence of Al 2 O 3 content ranging from 10 to 40 vol. % on densification, phase composition, microstructure, mechanical properties and oxidation behavior of the TaC-Al 2 O 3 composites was investigated. With 30 and 40 vol. % Al 2 O 3 addition a closed porosity was achieved. The Al 2 O 3 particles were uniformly distributed among TaC grains retarding grain growth and resulting in refined microstructures with grains below 2 μm in size. The most densified composite with 40 vol. % Al 2 O 3 addition exhibited good mechanical properties with a Vickers’ hardness of 17.8 GPa, a flexural strength of 485 MPa and a fracture toughness of 5.4 MPa·m 1/2 . After holding at 700°C for 3 h in air, the dense 30 and 40 vol. % Al 2 O 3 compositions showed hardly noticeable and mainly surface oxidation, whereas less densified TaC-Al 2 O 3 composites with 10 and 20 vol. % Al 2 O 3 content and with open porosity were disintegrated to powders.
研究领域:
材料科学
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机械工程
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产品关联
DOI
高影响因子
SOLID STATE IONICS
·
2013
·
IF 2.046
Yiqiu Li,Yang Cao,Xiangxin Guo
The lithium garnet ceramic has been considered as one of promising solid-state electrolytes for secondary lithium batteries . However, improvement of its ionic conductivity is hindered by the high porosity related to the severe volatilization of lithium components during sintering. In order to find the solution for this problem, Li 2 O additives in concentration of 2–8 wt.% were introduced into the cubic Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) at the solid-state reaction processes. It is found that the Li 2 O additives lead to formation of glassy-like phases at the grain boundaries related to the liquid-phase sintering behavior, which eliminates the residual pores therein and increases the relative density from 91.5% to 97.3%. Measurement of conductivity indicates that 6 wt.% is the optimum concentration of Li 2 O which leads to an ionic conductivity of 6.4 × 10 − 4 S cm − 1 at room temperature . This value is approximately 3 times larger than that of the ceramic without the additive.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2021
·Vol. 118
·期 36
·e2106061118
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IF 11.205
Xiang Wang,Qiang Gao,Xiaoning Han,Bing Bu,Longfei Wang,Aoqi Li,Linhong Deng
Mechanical forces generated by cells and the tension of the extracellular matrix (ECM) play a decisive role in establishment, homeostasis maintenance, and repair of tissue morphology. However, the dynamic change of cell-derived force during large-scale remodeling of soft tissue is still unknown, mainly because the current techniques of force detection usually produce a nonnegligible and interfering feedback force on the cells during measurement. Here, we developed a method to fabricate highly stretchable polymer-based microstrings on which a microtissue of fibroblasts in collagen was cultured and allowed to contract to mimic the densification of soft tissue. Taking advantage of the low-spring constant and large deflection range of the microstrings, we detected a strain-induced contraction force as low as 5.2 µN without disturbing the irreversible densification. Meanwhile, the microtissues displayed extreme sensitivity to the mechanical boundary within a narrow range of tensile stress. More importantly, results indicated that the cell-derived force did not solely increase with increased ECM stiffness as previous studies suggested. Indeed, the cell-derived force and collagen tension exchanged dramatically in dominating the microtissue strain during the densification, and the proportion of cell-derived force decreased linearly as the microtissue densified, with stiffness increasing to ∼500 Pa. Thus, this study provides insights into the biomechanical cross-talk between the cells and ECM of extremely soft tissue during large-extent densification, which may be important to guide the construction of life-like tissue by applying appropriate mechanical boundary conditions.
研究领域:
生物力学
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细胞生物学
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组织工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 106
·期 1
·722-737
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IF 4.186
Le Fu,Lei Li,Yongxin Cheng,Bohan Wang,Hui Wu
Morphology is an important characteristic of raw powder utilized for ceramic sintering but the role of powder morphology is mostly overlooked. In this study, two types of ZrO 2 –SiO 2 powder with different morphologies (fiber and particle) were synthesized by blow spinning and sol–gel method, respectively, followed by direct current electric field-assisted hot pressing (FAHP) to obtain nanocrystalline glass–ceramics (NCGCs). Results showed that the two as-synthesized powders had different pyrolysis behaviors. The two types of as-synthesized powders were amorphous and tetragonal-ZrO 2 nanocrystallites first formed after calcination at 800°C. During FAHP, the particle powder can be densified at a lower temperature than that of the fiber powder, due to the facts that the particle powder showed higher specific surface area and higher densification driving force. The fiber powder was predominately densified by fiber fusion and plastic deformation, whereas the particle powder was densified via particle fusion. Both the two types of powder can be fully densified to obtain ZrO 2 –SiO 2 NCGCs at 1230°C for 4 min. Tetragonal-ZrO 2 nanocrystallites in the NCGCs with particles as raw powder showed higher stability than those in the NCGCs with fibers as raw powder.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Zhaoqing Lu,Bo Geng,Qin Ma,Doudou Ning,Ruixia Zhao,Fangong Kong,Songfeng E
In this contribution, polyacrylic acid (PAA), polyacrylamide (PAM), thermoplastic polyurethane (TPU), and polyvinylpyrrolidone (PVP) were selected as additives to improve the mechanical strength and toughness of the aramid nanofiber (ANF) film. The results show that all these polymers can improve the strength, elongation at break, and toughness of the ANF film. Compared with pure film, the ANFs/TPU composite shows the highest strength of 273.14 MPa, an increase of 67.53%, and the ANFs/PAA exhibits the highest elongation of 30.02% and the highest toughness of 49.18 MJ·m −3 , increased by 251.52% and 304.77%, respectively. The enhancing mechanisms can be attributed to the structural densification, hydrogen bonding, and dipole–dipole interactions. The TPU and PAM that contain amide structures can form ordered networks of hydrogen bonds and show strong enhancing capacities on strength, while the PAA and PVP show robust enhancing capacities on toughness. Meanwhile, taking polystyrene (PS) as additive, we proved that the nonpolar polymer shows weak enhancing ability on the mechanical strength of ANF film due to the poor interfacial compatibility and severe phase separation.
研究领域:
材料科学
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纳米技术
·
高分子科学
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Jianliang Gong,Minhao Liao,Rihui Zhou,Haipeng Li,Abuduwaili Tuohuniyazi,Liqiong Xia,Zhipeng Wang,Yiwang Chen,Jie Feng,Xiaofang Zhang
Effectively transferring the excellent properties of carbon nanotubes (CNTs) at the microscopic scale to one-dimensional macroscopic materials has always been a cross-scale assembly challenge that researchers urgently need to address. In this paper, we present a synergistic dual-polymer-assisted acid spinning and viscoelastic interfacial densification technique, successfully assembling commercially available large-diameter, short-length, low aspect ratio, but easily mass-produced and cost-effective multiwalled carbon nanotubes (MWCNTs) into macroscopic functional fibers with continuous stacking structures, substantial mechanical strength, and good electrical conductivity. These “low-quality” MWCNTs, when processed into fibers using conventional nanomaterial assembly techniques, typically produce samples that are fragile and prone to breakage, with mechanical properties even failing to meet the minimum strength requirements for careful manual collection. We achieved breakthroughs through the following multiple synergistic actions: (1) utilizing the acid-soluble aromatic polyamide polymer Kevlar to assist in the uniform dispersion of MWCNTs in concentrated sulfuric acid (CSA); (2) using Kevlar as a “welding agent” to enhance the MWCNT stacking structure; (3) introducing the water-soluble polymer poly(vinyl alcohol) (PVA) to slow down the CSA-water exchange rate and reduce fiber surface disturbances; (4) inhibiting the gelation/solidification rate to extend the assembly and orientation time of MWCNTs; and (5) filling the pores left after the removal of CSA and water. Ultimately, we successfully prepared dual-polymer-doped CNT fibers (DP-CNTFs) with continuous mechanical collection strength for subsequent densification treatment. Taking advantage of the thermoplastic properties of PVA, we employed polytetrafluoroethylene as a viscoelastic interfacial layer to perform hot-press densification and defect repair on DP-CNTF, further enhancing its mechanical strength by 147.80% and electrical conductivity by over 770%. This technique not only overcomes the practical application bottleneck of continuously assembling and post-treating low-quality MWCNTs but also demonstrates its superiority in large-scale production and performance enhancement, providing a novel pathway for the industrialization of MWCNTs and their fibers.
研究领域:
材料科学
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纳米技术
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高分子科学
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碳材料
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纤维工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Jiangyu Zhang,Jie Li,Yihua Sun,Liang Fang
LiYbO 2 ceramic with tetragonal structure formed only by [LiO 6 ] and [YbO 6 ] octahedra, exhibited a ε r of 13.3 ± 0.2, Q × f of 24,700 ± 500 GHz and an abnormal positive τ f of + 38.6 ± 3.0 ppm/°C as sintered at 1100 °C with low relative density of 88 %. Dense ceramic with relative density of 95.1 % was obtained with the addition of 1 wt% LiF when sintered at 1080 °C, exhibiting enhanced microwave dielectric properties of ε r = 14.3 ± 0.2, Q × f = 41,200 ± 500 GHz, τ f = +56.5 ± 3.0 ppm/°C and α L = 8.5 × 10 −6 /K. The large positive discrepancy as much as + 45.1 % between measured ε r with porosity correction and calculated ε r (C-M) using Clausius−Mossotti relations might be due to the rattling effect of Li + , which also led to the positive τ f .
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Le Fu,Wenjun Yu,Bohan Wang
Ceramic sintering is an energy-consuming process. Reducing sintering temperature and shortening dwelling time are significant to the reduction of carbon footprint. It has been reported that utilizing mesoporous particles as raw powder for sintering is a promising strategy to achieve the above goal. The goal of this study is to verify if this strategy also works for the sintering of ZrO 2 –SiO 2 glass-ceramics. We synthesized mesoporous particles through a micelle-assisted co-precipitation process, followed by sintering by fast hot pressing (FHP) and pressureless sintering (PS) to obtain ZrO 2 –SiO 2 glass-ceramics. For comparison, solid particles without mesopores were synthesized by a sol-gel method and consolidated by the two sintering techniques. The densification behaviors of the two types of particles were comparatively investigated. Results showed that the mesopores collapsed at ∼850 °C during FHP due to the applied pressure, which resulted in a peak densification rate during the whole sintering process. The mesoporous particles (∼820 °C) had a lower densification starting temperature than that of the solid particles (∼910 °C). However, the mesoporous particles showed a longer densification process and a lower average densification rate than those of the solid particles. The samples sintered from mesoporous particles showed a heterogeneous microstructure, predominately consisting of ZrO 2 nanocrystallites embedded in a SiO 2 matrix, but in some regions ZrO 2 sub-microcrystallites were connected with each other by grain boundaries, without the presence of SiO 2 matrix. During PS, there was not significant differences in the densification between the mesoporous particles and the solid ones. These results demonstrated that the mesoporous particles did not show significant advantages over solid ones, in terms of the densification of ZrO 2 –SiO 2 glass-ceramics.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Songtong Xuan,Yuming Tian,Xiangchen Kong,Jianying Hao,Xiaojun Wang
The tuning of the properties of MgAl 2 O 4 -based materials has aroused great attention in the field of engineering technology. Along these lines, magnesia and alumina were used as raw materials to prepare spinel by the solid-phase sintering method at 1500–1600 °C. Particularly, the impacts of the different MgO/Al 2 O 3 molar ratios on the microstructural densification, sintering process and mechanical property of the fabricated materials were systematically studied. The results showed that the stoichiometric spinel with the highest concentration of ion diffusion possessed the best densification. And the magnesium-rich spinel displayed the better densification following with the formation of solid-solution, while the aluminum-rich spinel exhibited the worst ability in forming the solid-solution. Moreover, the different molar ratios changed the microstructure of the spinel, which induced the optimal sintering temperature of stoichiometric spinel to be at least 50 °C below that of the others. Specifically, in stoichiometric spinel, spinel grains grew up and formed obvious structure, which made the sintering process arrive at the end point and made the performance reach the best. Specifically, the flexural strength was 112.62 MPa and apparent porosity was 0.44%. However, no grown or developed spinel grains were observed for magnesium-rich/aluminum-rich spinels, which delayed the sintering process.
研究领域:
材料科学
·
无机非金属材料
·
陶瓷工艺学
·
固态化学
·
结构陶瓷
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shengtai Zhang,Zhen Teng,Linzhen Wu,Chen Chen,Yongqiang Tan,Xiaosong Zhou
Spark plasma sintering (SPS) is a fast and efficient method for preparing functional ceramics . This article investigates the phase evolution, thermal expansion and chemical stability of traditional (Y 1.2 Nd 1.8 Fe 5 O 12 ) and high-entropy ((Y, Gd, Sm, Eu, Dy) 3 Fe 5 O 12 ) garnet ceramics. Prepared under conventional SPS (50 MPa) conditions at 900–1100 °C. The results indicate that using SPS sintering method can significantly reduce the sintering temperature (1100 °C) and time (3 min) of garnet ceramics. (Y, Gd, Sm, Eu, Dy) 3 Fe 5 O 12 (1.6 × 10 −6 K −1 ) exhibits superior thermal expansion stability compared to Y 1.2 Nd 1.8 Fe 5 O 12 (5.4 × 10 −6 K −1 ). The strong REE-O bond energy and severe lattice distortion of high entropy garnet ceramics hinder the migration and diffusion of cations, resulting in higher leaching resistance of high-entropy garnet ceramics (∼10 −7 g m −2 d −1 -10 −8 g m −2 d −1 ) compared to traditional garnet ceramics (∼10 −5 g m −2 d −1 -10 −6 g m −2 d −1 ). Therefore, SPS has broad application prospects in the low-temperature preparation of high-entropy garnet ceramics for immobilization of actinide elements.
研究领域:
材料科学
·
陶瓷工程
·
核废料处理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Sen Liu,Shuaishuai Wu,Beibei Tang,Mao Chen,Yongqiang Chen,Hailong Wang,Rui Zhang,Bingbing Fan
High-density h-BN@SiC/ZrO 2 composites with different ZrO 2 contents were prepared by hot-pressing. The microstructure, flexural strength, thermal shock behavior, thermal expansion properties and corrosion resistance of the composites in molten steel were systematically investigated. The construction of the h-BN@SiC core-shell structure is conducive to the formation of a uniform and continuous network structure during the sintering process. This significantly improves the sintering performance of h-BN-based materials and enables the low-temperature preparation of high-density products. Moreover, the uniform distribution of SiC can effectively coordinate the thermal matching between h-BN and ZrO 2 , significantly improving the high-temperature performance of the material. During the corrosion process, the SiC network structure can effectively bind ZrO 2 and BN particles, effectively resist the erosion of high-temperature molten steel, and its erosion resistance increases with the increase of ZrO 2 content. Especially, when the ZrO 2 content reached 40%, the erosion depth of the sample was merely 160.61 μm after being immersed in static molten steel for 120 min. Moreover, the h-BN@SiC/ZrO 2 composite with 30 wt% ZrO 2 demonstrates superior comprehensive performance: It achieves a flexural strength of 159.63 MPa, retains 87.08% of its original strength after thermal shock testing, exhibits a low apparent porosity of 3.37%, and possesses an average coefficient of thermal expansion as low as 3.95 × 10 −6 /K −1 . The comprehensive properties of h-BN@SiC/ZrO 2 composites were obviously improved by SiC network structure.
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Chao Ma,Li Feng,Junpeng Cui,Zhipeng Hu,Qianqian Chu,Shipeng Xu,Weiqian Chen,Bo Chen,Putsiata Artur,Luoyi Zhang
To improve the service reliability of components used during spent nuclear fuel electrorefining, La 2 Zr 2 O 7 (LZO) protective coatings were prepared on SS 316L by atmospheric plasma spraying (APS) followed by vacuum annealing. The effects of annealing temperature and holding time on the phase structure, apparent porosity, and surface wettability of the LZO coatings were systematically investigated. The optimized coating was then exposed to KCl-LiCl molten salt at 600 °C for up to 640 h to evaluate its corrosion behavior and degradation mechanism. Annealing at 1200 °C for 2 h reduced apparent porosity from 18.96% to 8.21% and suppressed spreading of the salt-containing test solution. Within the initial 80 h, the as-sprayed and annealed coatings gained 1.3 and 0.6 mg·cm -2 , respectively, with apparent mass-change rates of 0.015 and 0.0075 mg·cm -2 ·h -1 . Both coatings shifted from mass gain to mass loss during 80-160 h, and the apparent mass-change rate of LZO-C640 reached -0.0525 mg·cm -2 ·h -1 . During 160-320 h, the apparent rates became positive as connected defects enabled deeper salt penetration and local interaction with the NiCrAlY bond coating. Preferential degradation of Al- and Cr-rich regions exposed and redistributed Ni-bearing material. NiO and NiCr 2 O 4 were subsequently detected at 320 h as secondary products. LaOCl was also detected at 320 h, whereas LiAlO 2 appeared after extended exposure. Throughout the final stage of 320-640 h, LZO-C640 maintained a low positive rate of 0.0075 mg·cm -2 ·h -1 . In contrast, the cumulative mass-change of H/LZO-C640 increased from -0.6 to -0.3 mg·cm -2 as its apparent rate approached zero. After 640 h, the annealed coating retained its overall skeleton, whereas the as-sprayed coating underwent top-layer disintegration. These results indicate that vacuum annealing did not completely prevent degradation, but limited molten-salt ingress and improved the long-term corrosion resistance of LZO coating.
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DOI
高影响因子
危险品化学品经营许可证（带存储）