Dielectric Properties of CaCu3Ti4O12 Synthesized by Different Routes

2014 ◽  
Vol 975 ◽  
pp. 184-188 ◽  
Author(s):  
Tatiane Cristina Porfirio ◽  
Eliana Navarro Santos Muccillo
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Dielectric Losses ◽  
Electric Permittivity ◽  
X Ray Diffraction ◽  
Soft Chemistry ◽  
X Ray ◽  
Powder Characteristics ◽  
Sintered Materials ◽  
Scanning Electron

The perovskite CaCu3Ti4O12, with giant electric permittivity, was prepared by a soft chemistry route and by the solid state synthesis technique. The main purpose of this work is to verify the effects of the synthesis techniques on the powder characteristics, and the microstructure and dielectric properties of the sintered materials. The synthesized nanopowders were calcined, pressed into pellets and sintered using the same procedures as for the materials prepared by the conventional method. Phase analysis was performed by X-ray diffraction, microstructure observations were carried out by scanning electron microscopy, and the dielectric properties were studied by impedance spectroscopy. The electric permittivity ranged from 11,600 to 27,000 and from 5,000 to 9,000 for specimens prepared by the conventional and the soft chemistry techniques, respectively, and the dielectric losses varied between 0.1 and 1.3 (conventional) and 0.095 and 0.3 (soft chemistry) depending on the sintering temperature.

Influence of Sintering Temperature on Densification and Microstructure of Zn3Nb2O8 Ceramics Derived from Nanopowders

2011 ◽  
Vol 194-196 ◽  
pp. 656-659 ◽  
Author(s):  
Phakkhananan Pakawanit ◽  
Supon Ananta
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Sintering Temperature ◽  
Density Measurement ◽  
Maximum Density ◽  
Dielectric Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dielectric Ceramics ◽  
Scanning Electron

Zinc niobate, Zn3Nb2O8, dielectric ceramics were fabricated by sintering Zn3Nb2O8 nanopowders derived from a rapid vibro-milling technique at various temperatures. Phase formation, densification, microstructure and dielectric properties of the ceramics were investigated as a function of sintering temperatures (1000-1200°C), using a combination of X-ray diffraction, Archimedes density measurement, scanning electron microscopy and dielectric measurement, respectively. It has been found that single-phase Zn3Nb2O8 ceramics with maximum density of ~98% theoretical density can be successfully produced with appropriate firing temperature, without any firing additives. Moreover, it is seen that the dielectric properties are found to enhance with increasing sintering temperature and grain size.

Microstructure and Microwave Dielectric Properties of Ba5(Nb1-xTax)4O15 (x = 0 ~ 0.5) Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 9-12 ◽  
Author(s):  
Fei Zhao ◽  
Zhen Xing Yue ◽  
Ying Chun Zhang ◽  
Zhi Lun Gui ◽  
Long Tu Li
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Large Range ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Relative Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Scanning Electron

The Ba5(Nb1-xTax)4O15 (x=0~0.5) solid-solution ceramics with hexagonal perovskite structure were prepared by solid-state oxide route. The phases and structure of the sintered ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influences of composition and sintering temperature on the bulk density, microstructure and microwave dielectric properties were also investigated. As the value of x increased from 0 to 0.5, the Q×f value increases from 36,049 to 49,493 GHz (at ~9GHz), whereas the dielectric constant (εr) decreases from 39.21 to 33.03 and the temperature coefficient of resonant frequency (τf ) decreases from 78.6 to 19.4 ppm/oC. The results indicate that the microwave dielectric properties of Ba5(Nb1-xTax)4O15 ceramics can be easily modified in a large range by changing the relative content of Ta to Nb.

Sinterability and Microwave Dielectric Properties of Li2CO3-V2O5 Added Mg4Nb2O9-CaTiO3 Composite Ceramics

2010 ◽  
Vol 663-665 ◽  
pp. 1196-1199
Author(s):  
Cui Jin Pei ◽  
Guo Guang Yao ◽  
Hong Ma ◽  
Xiu Lao Tian
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Microscopy Techniques ◽  
Co Doped ◽  
Scanning Electron

The effects of Li2CO3-V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of Mg4Nb2O9-CaTiO3 composite ceramics have been investigated. The phase compositions and microstructure were analyzed using X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy techniques. The densification sintering temperature is lowed from 1275oC to 1200oC with an amount LV addition. For the specimen with 1.5 wt% LV addition sintered at 1200oC for 5 h exhibited dielectric properties: εr=23, Q·f=24 000 GHz (at 7.7GHz ), τf =1.0 ppm/oC. These properties were correlated with the formation of non-stoichiometric compound Mg4(Nb1-xTix)2O9-δ.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Phase Development and Dielectric Properties of 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3 Ceramic

2011 ◽  
Vol 700 ◽  
pp. 58-62
Author(s):  
Rachanusorn Roongtao ◽  
Supagorn Rugmai ◽  
Wanwilai C. Vittayakorn
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Phase Development ◽  
Scanning Electron

The 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3ceramics has been synthesized through a conventional mixed-oxide by using BT nanopowder and BMN micropowder. The phase purity of the powders and the ceramics was examined using X-ray diffraction (XRD). The 0.98BT-0.02BMN powders were sintered to 92% of the theoretical density at a temperature of 1300 °C for 2 h. The microstructure of the sintered surface was investigated using scanning electron microscopy (SEM). The dielectric constant (εr) and loss factor (tanδ) of the sintered pellets at Curie temperture were 3000 and 0.015, respectively.

scholarly journals Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics

2021 ◽  
Author(s):  
Haiquan Wang ◽  
Shixuan Li ◽  
Kangguo Wang ◽  
Xiuli Chen ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Bulk Density ◽  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Microwave Dielectrics ◽  
X Ray ◽  
Microwave Dielectric ◽  
Sintering Behaviour

AbstractThis study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.

scholarly journals Pengaruh Suhu Sintering Terhadap Sintesis Silicon Carbide (SiC) Berbahan Dasar Abu Sekam Padi dan Grafit Pensil 2B

2015 ◽  
Vol 5 (01) ◽  
pp. 31
Author(s):  
Resky Irfanita ◽  
Asnaeni Ansar ◽  
Ayu Hardianti Pratiwi ◽  
Jasruddin J ◽  
Subaer S
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Rice Husk Ash ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Scanning Electron

The objective of this study is to investigate the effect of sintering temperature on the synthesis of SiC produced from rice husk ash (RHA) and 2B graphite pencils. The SiC was synthesized by using solid state reaction method sintered at temperatures of 750°C, 1000°C and 1200°C for 26 hours, 11.5 hours and 11.5 hours, respectively. The quantity and crystallinity level of SiC phase were measured by means of Rigaku MiniFlexII X-Ray Diffraction (XRD). The microstructure of SiC was examined by using Tescan Vega3SB Scanning Electron Microscopy (SEM). The XRD results showed that the concentration (wt%) of SiC phase increases with the increasing of sintering temperature. SEM results showed that the crystallinity level of SiC crystal is improving as the sintering temperature increases

Preparation and Microstructure of Pressureless Sintered Si2ON2-SiC Ceramic

2011 ◽  
Vol 335-336 ◽  
pp. 699-703
Author(s):  
Hui Hui Tan ◽  
Zhu Xing Tang ◽  
Xia Zhao ◽  
He Zhang
Keyword(s):  
Bulk Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Nitriding Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Additives ◽  
Sic Ceramic ◽  
Sintering Method ◽  
Scanning Electron

This paper introduces Si2ON2-SiC ceramic fabricated by pressureless sintering method and studies the effect of additives, nitriding temperatures on bulk density, porosity, phase composition and microstructure. It is discovered that additives MgO, CeO2 can increase the densities of Si2ON2-SiC ceramic apparently, and MgO additive has a better effect than CeO2. Nitriding temperature also is an important factor. The bulk density of the specimen with MgO additive reaches maximum at 1.91 g/cm3 when sintered at 1450 °C, and the bulk density of specimen with CeO2 additive is 1.86 g/cm3 at the same condition while the bulk density of the specimen without additive is only 1.75 g/cSuperscript textm3. The X-ray diffraction and scanning electron microscopy of the specimens show that the amount of Si2ON2 increase with the sintering temperature increase. But when the temperature is higher than 1500 °C the Si2ON2 grains will decompose into Si3N4, and Si2ON2 will vanish at 1550 °C

Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lanthanum Content ◽  
Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

Preparation of the System of BaO-MgO-Al2O3-TiO2 Acid-Resistant Fracturing Proppants

2011 ◽  
Vol 399-401 ◽  
pp. 855-859
Author(s):  
Ting Ting Wu ◽  
Bo Lin Wu
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Acid Resistance ◽  
Pressureless Sintering ◽  
Alumina Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Solubility ◽  
Resistance Performance ◽  
Scanning Electron

In order to improve the acid resistance and reduce the apparent density of fracturing proppants, TiO2 powder added in the system of BaO-MgO-Al2O3 fracturing proppants were prepared by the technique of pressureless sintering. The properties of the samples were investigated by the measurements of acid solubility, X-ray diffraction and scanning electron microscopy. The results show that the acid solubility of alumina matrix fracturing proppants contenting TiO2 of the 4wt% and BaO/MgO with the ratio of 3:7 is 0.15%. It is an important development in acid resistance performance of fracturing proppants research on laboratory. TiO2 is added to the raw materials and then calcine them to ceramics, which can reduces the sintering temperature, promote the densification and improve acid-resistant property of fracturing proppants.

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