Core-Shell Structure and Dielectric Properties of Ba0.6Sr0.4TiO3@ Fe2O3 Ceramics Prepared by Co-Precipitation Method

Ba0.6Sr0.4TiO3 (BST) ceramic materials have been widely used in the field of multilayer ceramic capacitors. Surface modification through the surface coating to form a heterogeneous layer could effectively improve the dielectric properties. In this work, BST powders were prepared by a co-precipitation method. The effects of reaction conditions on the microstructure of the BST powder were investigated. The reaction temperatures significantly affected the morphology of BST powder, and the rhombic-type particles were obtained with the reaction temperature around 80 °C. Meanwhile, the BST@Fe2O3 was prepared by the chemical precipitation method using BST powders with rhombic-type microstructure as “core”, and the so-called “core-shell” microstructure was confirmed in the BST@Fe2O3 powder. Then, BST@x wt%Fe2O3 (x = 2.5, 5, 7.5, and 10, denoting the different content of Fe2O3) ceramics were further prepared, and the influence of “core-shell” structure on the phase structure, microstructure, and dielectric properties was investigated. With the increasing of Fe2O3 content, the ferroelectric–paraelectric phase transition temperature shifts toward lower temperatures, and dielectric peaks gradually become broad and frequency-dependent, which may be due to inconsistent chemical composition from core to shell.

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Preparation of Amorphous Calcium Phosphate/Triclcium Silicate Composite Powders

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1643 ◽

2009 ◽

Vol 79-82 ◽

pp. 1643-1646 ◽

Cited By ~ 1

Author(s):

Qing Lin ◽

Yan Bao Li ◽

Xiang Hui Lan ◽

Chun Hua Lu ◽

Zhong Zi Xu

Keyword(s):

Calcium Phosphate ◽

Shell Structure ◽

Amorphous Calcium Phosphate ◽

Chemical Precipitation ◽

Precipitation Method ◽

Core Shell ◽

X Ray Diffraction ◽

Composite Powders ◽

X Ray ◽

Core Shell Structure

The amorphous calcium phosphate (ACP)/tricalcium silicate (Ca3SiO5, C3S) composite powders were synthesized in this paper. The exothermal behavior of C3S determined by isothermal conduction calorimetry indicated that the ACP could be synthesis by chemical precipitation method during the induction period (stage II) of C3S. The composite powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results indicated that nanosized ACP particles deposited on the surface of C3S particles to form core-shell structure at pH=10.5, and the nCa/nP of ACP could be controlled between 1.0 and 1.5. The core-shell structure is stable after sintered at 500 oC for 3 h to remove the β-cyclodextrin (β-CD). As compared with the irregular C3S particles (1~5 μm), the composite powders particles are spherical with a diameter of 40~150 μm. Therefore, to obtain the smaller size of composite powders, it is expected to avoid the aggregate of C3S particles in the aqueous solution by addition of dispersant. As compared with C3S, the composite powders may contribute better injectability, strength and biocompatibility.

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Preparation and Optical Property of ZnS:Mn/XO2 (X=Ti, Si) Nanoparticles with Core/Shell Structure

Materials Science Forum ◽

10.4028/www.scientific.net/msf.814.376 ◽

2015 ◽

Vol 814 ◽

pp. 376-383

Author(s):

Yu Long Wang ◽

Wen Tao Zhang ◽

Jian Ping Long ◽

Pei Cong Zhang

Keyword(s):

Optical Property ◽

Luminescence Intensity ◽

Shell Structure ◽

Precipitation Method ◽

Molar Ratio ◽

Tetrabutyl Titanate ◽

Core Shell ◽

Si Nanoparticles ◽

Core Shell Structure ◽

Co Precipitation

In this paper, Mn2+ doped ZnS (ZnS:Mn) nanoparticles were prepared by co-precipitation method. And then different thickness of TiO2 and SiO2 inorganic shell were coated on prepared ZnS:Mn through the hydrolysis reaction of tetrabutyl titanate (TBOT) and tetraethyl orthosilicate (TEOS). ZnS:Mn crystal and core/shell structure were described by X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical property of all ZnS:Mn/XO2 (X=Ti, Si) nanoparticles were investigated by photoluminescence (PL) spectrometer. The effect of Mn2+ concentration and XO2 (X=Ti, Si) shell thickness on luminescence intensity of ZnS:Mn/XO2 was studied. The results showed that with TiO2 and SiO2 shell thickening, Mn2+ emission of ZnS:Mn/XO2 samples increased first and then decreased. When the thickness of inorganic shell (molar ratio of shell and core amount) reached to 0.5 (TiO2) and 1.0 (SiO2), the optimal luminescence intensity was obtained. The emission of ZnS:Mn/TiO2 and ZnS:Mn/SiO2 was 2.0 and 1.5 times more in intensity than that of uncoated ZnS: Mn, respectively.

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Fabrication of submicron BaTiO3@YFeO3 particles and fine-grained composite magnetodielectric ceramics with a core–shell structure by means of a co-precipitation method

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-017-6880-z ◽

2017 ◽

Vol 28 (15) ◽

pp. 10986-10991

Author(s):

Rong Ma ◽

Yan Wang ◽

Bin Cui ◽

Yanjun Wang ◽

Yaoyu Wang

Keyword(s):

Shell Structure ◽

Precipitation Method ◽

Core Shell ◽

Fine Grained ◽

Core Shell Structure ◽

Co Precipitation

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THERMODYNAMIC AND KINETIC ANALYSES OF SYNTHESIZING ZrB2@Al(OH)3–Y(OH)3 CORE–SHELL COMPOSITE PARTICLES

Surface Review and Letters ◽

10.1142/s0218625x07009190 ◽

2007 ◽

Vol 14 (01) ◽

pp. 117-122 ◽

Cited By ~ 4

Author(s):

JIEGUANG SONG ◽

LIANMENG ZHANG ◽

JUNGUO LI ◽

JIANRONG SONG

Keyword(s):

High Temperature ◽

High Performance ◽

Solubility Product ◽

Ceramic Materials ◽

Precipitation Method ◽

Composite Particles ◽

Core Shell ◽

High Temperature Strength ◽

Co Precipitation ◽

Shell Composite

ZrB 2 has some excellent performances, but it is easily oxidized at high temperatures to impact the high-temperature strength, which restricts its applied range. To protect from the oxidization and improve the strength of ZrB 2 at high temperature, the surface of ZrB 2 particles is coated with the Al ( OH )3– Y ( OH )3 shell to synthesize ZrB 2@ Al ( OH )3– Y ( OH )3 core–shell composite particles. Through the thermodynamic and kinetic analyses of the heterogeneous nucleation and homogeneous nucleation, the concentration product of precursor ion ( Y 3+ or Al 3+) and OH - (Qi) must be greater than the solubility product (K sp ), respectively; the conditions of Y 3+ and Al 3+ are reached to produce Al ( OH )3– Y ( OH )3 shell on the ZrB 2 surface between the Y 3+ line and the AlO 2- line. Through TEM and XRD analyses, ZrB 2@ Al ( OH )3– Y ( OH )3 core–shell composite particles are successfully synthesized by the co-precipitation method, the shell layer quality is better at pH = 9, which established the foundation for preparing high-performance YAG / ZrB 2 and Al 2 O 3– YAG / ZrB 2 multiphase ceramic materials.

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Preparation and dielectric properties of Ba((Fe0.5Nb0.5)O3/Al2O3 composite ceramics with core/shell structure

2015 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF), International Symposium on Integrated Functionalities (ISIF), and Piezoelectric Force Microscopy Workshop (PFM) ◽

10.1109/isaf.2015.7172683 ◽

2015 ◽

Author(s):

Zhuo Wang ◽

Chun Wang ◽

Mingrui Fang ◽

Yongfei Wen ◽

Haijuan Li

Keyword(s):

Dielectric Properties ◽

Shell Structure ◽

Core Shell ◽

Composite Ceramics ◽

Core Shell Structure

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Production of Ba 0.991 Bi 0.006 TiO 3 @ZnO–B 2 O 3 –SiO 2 ceramics with a high dielectric constant, a core–shell structure, and a fine-grained microstructure by means of a sol-precipitation method

Ceramics International ◽

10.1016/j.ceramint.2016.01.143 ◽

2016 ◽

Vol 42 (6) ◽

pp. 7397-7405 ◽

Cited By ~ 10

Author(s):

Mengqian Shangguan ◽

Bin Cui ◽

Rong Ma ◽

Yaoyu Wang

Keyword(s):

Dielectric Constant ◽

Shell Structure ◽

High Dielectric Constant ◽

Precipitation Method ◽

Core Shell ◽

Fine Grained ◽

Core Shell Structure ◽

High Dielectric

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Core-Shell Structure and Dielectric Properties of Ba0.991 Bi0.006 TiO3 @Nb2 O5 -Co3 O4 Ceramics

Journal of the American Ceramic Society ◽

10.1111/jace.14154 ◽

2016 ◽

Vol 99 (5) ◽

pp. 1664-1670 ◽

Cited By ~ 18

Author(s):

Yu Liu ◽

Bin Cui ◽

Yan Wang ◽

Rong Ma ◽

Mengqian Shangguan ◽

...

Keyword(s):

Dielectric Properties ◽

Shell Structure ◽

Core Shell ◽

Core Shell Structure

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Enhanced Dielectric Properties of Ferroelectric Polymer Composites Induced by Metal-Semiconductor Zn-ZnO Core–Shell Structure

ACS Applied Materials & Interfaces ◽

10.1021/am2016156 ◽

2012 ◽

Vol 4 (1) ◽

pp. 65-68 ◽

Cited By ~ 106

Author(s):

Ye Zhang ◽

Yao Wang ◽

Yuan Deng ◽

Mao Li ◽

Jinbo Bai

Keyword(s):

Dielectric Properties ◽

Polymer Composites ◽

Shell Structure ◽

Core Shell ◽

Ferroelectric Polymer ◽

Core Shell Structure

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Microstructures and Highly Accelerated Lifetime Test of X5R Type BaTiO3-Based Ni-MLCC with Ultra-Thin Active Layers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.695 ◽

2014 ◽

Vol 602-603 ◽

pp. 695-699

Author(s):

Hui Ling Gong ◽

Xiao Hui Wang ◽

Shao Peng Zhang ◽

Xin Ye Yang ◽

Long Tu Li

Keyword(s):

Dielectric Properties ◽

Shell Structure ◽

Casting Process ◽

Thin Layers ◽

Core Shell ◽

Active Layers ◽

Transmission Electron ◽

Lifetime Test ◽

Accelerated Lifetime ◽

Core Shell Structure

Microstructure control in thin-layer multilayer ceramic capacitors (MLCCs) is one of the challenges for increasing capacitive volumetric efficiency and high voltage dielectric properties. In this paper, the X5R-MLCCs with ultra-thin dielectric layers (~1.2 μm) owning uniform grain size distribution were prepared by wet casting process. The microstructures and dielectric properties of the MLCCs were investigated. The existence of core-shell structure was proved by transmission electron microscopy observation and energy dispersive spectroscopy analysis. The existence of core-shell structure makes the temperature coefficient of capacitance (TCC) performance meet X5R standard. Moreover, a highly accelerated lifetime test (HALT) result shows that MLCCs with ultra-thin layers under high electric field are more easily to fail with increasing test temperatures. And the results reveal that the activation energy is similar to the value reported for mid-dielectric constant dielectrics.

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