POWDER TECHNOLOGY
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2024
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IF 4.5
Huifeng Xu,Pengfei Wang,Saiwei Luan,Lixia Cheng,Zhenxiao Fu,Xiuhua Cao,Lei Zhang,Shuhui Yu,Rong Sun
Conventionally, tetragonality in BaTiO 3 powder is attributed to grain size, disregarding the role of Ba/Ti ratio. However, our study reveals a significant impact of Ba/Ti ratio on tetragonality in BaTiO 3 . With an increase in Ba/Ti ratio from 0.990 to 1.010, particle size remains around 200 nm. Tetragonality initially rises from 1.006 to a maximum of 1.0092 at Ba/Ti = 1.000, then decreases to 1.005. Lower tetragonality is associated with Ba or Ti vacancies, using density functional theory (DFT), we analyzed the electron density and lattice distinction in BaTiO 3 powders. Both Ba and Ti vacancies affect lattice distortion, the Ti vacancies leading to more significant lattice expansion and lower tetragonality than Ba vacancies. Using this powder, we fabricated high-density BaTiO 3 ceramics and multi-layer ceramics capacitors (MLCCs) with X7R temperature stability (−55 to 125 °C, ±15% coefficient) and excellent reliability. This strategy has broad implications for tetragonal BaTiO 3 nanopowders and MLCCs development.
研究领域:
材料科学
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无机非金属材料
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电子陶瓷
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固态化学
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功能材料
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2017
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IF 2.084
Guanghao Li,Yang Zhao,Jiao Xu,Zhiyong Mao,Jingjing Chen,Dajian Wang
Two strategies, deviation of stoichiometry and addition of flux, were employed in this work to suppress the emergence of AlN impurity in the synthesis of CaAlSiN 3 :Eu 2+ phosphors under condition of atmospheric pressure. The influence of Al atoms deviation from ideal stoichiometry and SrF 2 flux addition on the suppression of AlN impurity and their resultant photoluminescence properties are investigated for CaAlSiN 3 :Eu 2+ phosphors. For a special Eu 2+ doping concentration (0.02 mol), AlN impurity was suppressed effectively when Al element deviation is 0.2 mol (CaAl 0.8 SiN 3 ) and the SrF 2 flux addition is 7 wt% during preparation of CaAlSiN 3 :Eu 2+ phosphors, respectively. The luminescent properties of CaAlSiN 3 :Eu 2+ phosphors are found to be enhanced significantly owing to the suppression of AlN impurity. In addition, the suppression mechanisms of AlN impurity in atmospheric pressure-synthesized CaAlSiN 3 :Eu 2+ phosphors are discussed. These results indicate the promising prospect for our proposed strategies in preparing high performance CaAlSiN 3 :Eu 2+ phosphors under the condition of atmospheric pressure.
研究领域:
材料科学
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无机化学
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固体发光
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功能材料
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光电子学
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2021
·
IF 5.234
Siqi Xiang,Xingjian Du,Yihan Liang,Mengcheng Zhou,Xinfang Zhang
Full density TiC reinforced Cu matrix composites are fabricated by electropulsing-assisted flash sintering within 40 s. The addition of TiC significantly increases the hardness of the sintered sample. However, liquid Cu does not wet stoichiometric TiC, leading to a poor interface bonding strength between TiC and Cu, thus the tensile strength of the sintered sample is destroyed. By adding a small amount of Ti, the bonding strength of the interface between TiC and Cu can be effectively optimized, thereby the mechanical strength of the samples is improved, showing an increased hardness and tensile strength . Skillfully use the relationship between hardness and tensile strength curve to intuitively show the bonding strength of the micro interface from the macro characteristics. The reaction between dissolved Ti and stoichiometric TiC and the decomposition of stoichiometric TiC cause the formation of near-surface non-stoichiometric TiC x ( x < 1) with a marked metal-like electronic structure, which is the fundamental reason for the optimization of the interface bonding between TiC particles and Cu matrix. In the process of powder metallurgy , it is a promising strategy to enhance the composite materials by adjusting the stoichiometry of ceramic to form metal-like electronic structure and alter the bonding strength of ceramic/metal interface.
研究领域:
材料科学
·
粉末冶金
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金属基复合材料
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界面工程
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固态加工
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2015
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IF 2.999
Jingwei Gu,Ying Zeng,Xiaofang Feng,Ximin Wu,Chunmei Zeng,Mingqi Li
Nanosilicon@nonstoichiometric silicon oxide where nanosilicon is embedded in SiO x matrix (abbreviated as nano-Si@SiOx), is a very attractive material structure to suppress the volume effect of silicon in Lithium-ion batteries. In this work, we demonstrate that the combination of electrolysis and peeling technique produce nano-Si@SiOx from bulk SiO 2 . X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) are employed to characterize the prepared materials. The average O/Si atomic ratio of the synthesized nano-Si@SiOx is about 0.91. The nano-Si@SiOx/graphite composite prepared using it as the precursor exhibits a stable discharge capacity of about 1560 mAh g −1 (calculated on the total mass of the composite) with good cyclic stability and rate capability. This work provides a new routine to prepare nano-Si@SiOx composite.
研究领域:
材料科学
·
电化学
·
纳米材料
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能源存储
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锂离子电池
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）