Sintering and Dielectric Properties of SrTiO3-based Ceramics

2012 ◽  
Vol 1397 ◽  
Author(s):  
Juan Li ◽  
Dengren Jin ◽  
Lixin Zhou ◽  
Jinrong Cheng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Precursor Solution ◽  
Particle Sizes ◽  
Low Dielectric ◽  
Different Temperatures ◽  
High Dielectric ◽  
Room Temperature Dielectric Constant

ABSTRACTHigh dielectric tunability, low dielectric loss tangent and appropriate level of dielectric constant are the basic requirements for applications as electrically tunable dielectric microwave devices. In our experiments, the SrTiO3 green compacts made of the powder mixtures with various particle sizes were infiltrated with a BaTiO3 precursor solution and sintered at different temperatures between 1280 and 1350 ºC for 2 hours and 1350 ºC for 6 hours. The sintering, microstructural and dielectric properties were investigated. Results showed that the relative density of SrTiO3 ceramics could reached 93% when sintered at 1280 ºC for 2 hours. When sintered for 6 hours at 1350 °C, the room temperature dielectric constant of SrTiO3 reaches 900 at a frequency of 1MHz. It has only weak temperature dependence between 100 and 500K. The reason of the low sintering temperature for the dense SrTiO3 ceramics and the effects of sintering scheme on the dielectric properties from 100 K to 500 K are discussed in this paper.

Effect of Pb Volatilization on Dielectric Properties of 0.77PbMg1/3(Nb0.9Ta0.1)2/3O3-0.23PbTiO3

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3738-3744 ◽  
Author(s):  
C. Zhang ◽  
J. T. Wang ◽  
M. Q. Qian ◽  
T. P. Chen ◽  
I. Akujobi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Lead Magnesium Niobate ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Different Temperatures ◽  
Lead Magnesium ◽  
High Dielectric ◽  
The Cost

Lead magnesium niobate-lead titanate (PMN-PT) is an intriguing candidate for applications in many electronic devices such as multi-layer capacitors, electro-mechanical transducers etc. because of its high dielectric constant, low dielectric loss and high strain near the Curie temperature. As an extension of our previous work on Ta-doped PMNT-PT aimed at optimizing the performance and reducing the cost, this paper focuses on the effect of Pb volatilization on the dielectric properties of 0.77 Pb ( Mg 1/3( Nb 0.9 Ta 0.1)2/3) O 3-0.23 PbTiO 3. The dielectric constant and loss of the samples are measured at different frequencies and different temperatures. The phase purity of this compound is determined by X-ray diffraction pattern. It is found that the volatilization during sintering does influence the phase formation and dielectric properties. The best condition is sintering with 0.5 g extra PbO around a 4 g PMNT-PT sample.

Morphology and Dielectric Properties of Boron-doped BaTiO3

2013 ◽  
Vol 32 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Zhuo Qun Zheng ◽  
Xiao Ping Zhou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Dielectric Strength ◽  
Optimum Composition ◽  
Boron Doped ◽  
Boron Dopant ◽  
Room Temperature Dielectric Constant

AbstractBoron-doped BaTiO3 precurors (BaTi1−xB2xO3+X) were prepared via the glycol-glycerol complexes of boron, titanium (IV), and barium. With optimum composition, ceramics with dielectric properties comparable to those of pristine BaTiO3 ceramic sintered at 1300°C can be obtained after sintered at temperature less than 900°C (room-temperature dielectric constant ∼4000, dielectric strength ∼7.0 kV/mm). The appreciable decrease in sintering temperature is attributable to (a) addition of boron dopant as substitute of titamium rather than to stochiometric BaTiO3, and (b) application of glycol-glycerol solvents/ligands in the synthesis of precursors, which guarantees the compositional homogenization of the final ceramics.

Dielectric Properties of Low-Temperature Sintered Ba0.6Sr0.4TiO3 Ceramics by Addition of Bi2O3-CuO Mixed Oxides

2009 ◽  
Vol 421-422 ◽  
pp. 61-64 ◽  
Author(s):  
Hai Tao Jiang ◽  
Ji Wei Zhai ◽  
Jing Ji Zhang ◽  
Xi Yao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Mixed Oxides ◽  
Sintering Temperature ◽  
Low Dielectric ◽  
High Tunability ◽  
Dc Electric Field ◽  
Bst Ceramics

The effect of 9Bi2O3-CuO mixed oxides as sintering agent on sintering behaviors and dielectric properties of Ba0.6Sr0.4TiO3 (BST) ceramics were investigated. It was found that 9Bi2O3-CuO mixed oxides lowered the sintering temperature about 300°C and that highly denser BST ceramic pellets were obtained by sintering at 975oC with addition of 5.0-10.0wt% mixed oxides. For BST ceramics with 5.0wt% CB content sintered at 975°C, had a moderate dielectric constant (ε=1315), low dielectric loss (0.0067) and high tunability (36%) at dc electric field of 20kV/cm and at room temperature and at 10kHz.

Effect of Sintering Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics Prepared by Mechanochemical Process

2014 ◽  
Vol 974 ◽  
pp. 157-161
Author(s):  
Masturah Mohamed ◽  
Mahesh Talari ◽  
Mohd Salleh Mohd Deni ◽  
Azlan Zakaria
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Processing Conditions ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Grain Sizes ◽  
Barrier Capacitance ◽  
Different Temperatures ◽  
Increasing Temperature

CaCu3Ti4O12(CCTO) is well known to have colossal dielectric constant in the range of 105.It is widely accepted that this phenomenon may be attributed to internal layer barrier capacitance (IBLC) model. The dielectric properties of CCTO were reported to be strongly dependent on the processing conditions and grain size. In this work, CCTO samples with different grain sizes were produced by varying sintering temperature in order to investigate IBLC effect on dielectric properties of CCTO. The samples were sintered at four different temperatures, (T=1100°C, 1050°C, 1000°C and 950°C). Dielectric measurements were carried out for the samples in the frequency range of 102– 106Hz using impedance spectrometer. Electron micrographs showed that increasing temperature promoted the grain growth of CCTO while sintering. The internal crystalline defects are seen to play major role by increasing the grain conductivity in dipole formation and increased the dielectric constant of the samples.

Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites

2016 ◽  
Vol 848 ◽  
pp. 28-31
Author(s):  
Han Jin ◽  
Yong Feng Li ◽  
Zhong Qi Shi ◽  
Hong Yan Xia ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
Dielectric Constant ◽  
Phase Composition ◽  
High Temperature ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Different Temperatures

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.

DIELECTRIC PROPERTIES OF CHEMICALLY SYNTHESIZED PbTiO3 NANOCRYSTALS SUITABLE FOR HIGH FREQUENCY DEVICES

2010 ◽  
Vol 24 (23) ◽  
pp. 4547-4554
Author(s):  
K. C. VERMA ◽  
M. SINGH ◽  
N. THAKUR ◽  
N. S. NEGI
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Xrd Pattern ◽  
High Frequency Devices ◽  
Room Temperature Dielectric Constant ◽  
Transmission Scanning Electron Microscopy

PbTiO 3 (PT) nanoparticles have been prepared by chemical route using polyvinyl alcohol (PVA) as an efficient surfactant. The effect of PVA to reduce the particle's sizes of PT has been observed. X-ray diffraction (XRD) pattern shows that the PT nanoparticles are tetragonal with distortion ratio, c/a ~1.061. The average particle's size calculated from XRD and transmission/scanning electron microscopy is ~24 nm for PT powder sintered at 700°C. The nanostructured grains were also observed in PT pellet sintered at 1000°C. The dielectric properties of PT pellet have been measured from room temperature to 200°C and in the frequency range of 0.075 to 10 MHz. The values of room temperature dielectric constant and tanδ are 117 and 0.05 respectively, measured at 0.5 MHz. It is found that the dielectric constant of PT nanoparticles can be controlled up to higher frequency region of 5 MHz.

Dielectric Properties of Li-Doped CaCu3Ti4O12 Ceramics

2011 ◽  
Vol 687 ◽  
pp. 251-256 ◽  
Author(s):  
Ying He ◽  
Huai Wu Zhang ◽  
Yuan Xun Li ◽  
Wei Wei Ling ◽  
Yun Yan Wang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Secondary Phase ◽  
Doping Amount ◽  
Spectroscopy Analysis ◽  
Low Dielectric ◽  
Tan Δ ◽  
High Dielectric ◽  
Impedance Spectroscopy Analysis

CaCu3Ti4O12 ceramics doped with 0-2.0 wt% Li2CO3 were prepared by the solid-state reaction, and their electric and dielectric properties were investigated. It is found that these ceramics had the properties of high dielectric constant and comparatively low dielectric loss. At the doping amount of 0.5 wt%, the dielectric constant is kept to be 105 with weak frequency dependence below 105 Hz, and its loss tangent (tan δ) is suppressed below 0.1 between 300 Hz-5 kHz (with the minimum value of 0.06 at 1 kHz from 218 K to 338 K). The impedance spectroscopy analysis confirms that the decrease of dielectric loss is mainly due to the increase of resistance in the grain boundary, which may be related to the influence of Ti4O7 secondary phase. Our result indicates that doping Li2CO3 is an efficient method to optimize the dielectric properties of CaCu3Ti4O12.

Effect of Platinum Substitution on the Microstructures and Dielectric Relaxation of CaCu3Ti4O12 Ceramics

2013 ◽  
Vol 802 ◽  
pp. 134-138 ◽  
Author(s):  
Worawut Makcharoen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Ferroelectric Materials ◽  
X Ray Diffraction ◽  
High Loss ◽  
Internal Barrier Layer Capacitor ◽  
High Dielectric

The CaCu3Ti4O12(CCTO) has the advantage for the various applications especially for capacitive elements in microelectronic devices over the ferroelectric materials including BaTiO3. CCTO is a ceramic compound with a high dielectric constant but it has a high loss tangent at room temperature. In this work, the Influences of PtO2doping on the dielectric properties of CaCu3Ti4O12(CCTO) ceramics were investigate. The ceramics CCTO and PtO2doping CCTO were studied by X- ray diffraction, scanning electron microscopy. The dielectric properties have been measured as a function of temperature and frequency range 0.1 - 500 kHz. The XRD shows the CCTO structure does not changes after doping with platinum. The results show that PtO2doped can reduce the mean grain sizes of CCTO, but the dielectric constant still remained a height. The samples of 2.0 mol% Pt-doped have exhibited high dielectric constant of about 22,000 and the loss tangent about 0.7 at room temperature and frequency at 10 kHz. The reduced of the loss tangent could be interpreted with the internal barrier layer capacitor model (IBLC)

Dielectric Properties of CaCu3Ti4O12-P(VDF-TrFE) Composite

2006 ◽  
Vol 949 ◽  
Author(s):  
Xiaobing Shan ◽  
Xin Yang ◽  
Kewei Zhang ◽  
Zhongyang Cheng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Powder Processing ◽  
Ceramic Powders ◽  
Casting Method ◽  
Uniform Size ◽  
Solution Casting Method ◽  
High Dielectric ◽  
Conventional Solution

ABSTRACTBy using conventional solution casting method, a flexible ceramic [CaCu3Ti4O12 (CCTO)]-Polymer [P(VDF-TrFE)] composite has been fabricated. The CCTO ceramic powders with a relative uniform size were prepared by traditional powder processing method. The dielectric properties of these films with different CCTO fractions were determined. The process was optimized to achieve high dielectric constant. A dielectric constant about 510 at room temperature and 1240 at 95 °C at 1 kHz for 6 layer hot compression was obtained.

Three-Step Deposition Method for Improvement of the Dielectric Properties of BST Thin Films

2012 ◽  
Vol 1397 ◽  
Author(s):  
H. Liu ◽  
V. Avrutin ◽  
C. Zhu ◽  
J.H. Leach ◽  
E. Rowe ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Step Method ◽  
Bst Thin Films ◽  
Different Temperatures ◽  
Different Strains ◽  
High Dielectric

ABSTRACTEpitaixal Ba0.5Sr0.5TiO3 (BST) thin films were grown on SrTiO3 (STO) and DyScO3 substrates by radio-frequency magnetron sputtering system using three-step method which involves a relatively low-temperature (573-773 K) growth of a BST interlayer sandwiched between two BST layers deposited at a high substrate temperature of 1068 K. X-ray diffraction measurement showed different strains on the films with interlayers grown at different temperatures. Post-growth thermal treatment reduced film strain to a great extent (the film strain of a tri-layer film with a 773 K grown interlayer is only -0.001). Comparing with the control films grown at high temperature, three-step technique improved the dielectric properties, especially increased dielectric constant by 60% for BST/STO and 31% for BST/DyScO3, respectively. High dielectric constant of 1631.4 and its tuning of 36.7% were achieved on the BST/STO with an interlayer grown on 773 K.

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