scholarly journals Effects of W6+ substitution on the microwave dielectric properties of Ce2Zr3(MoO4)9 ceramics

2019 ◽  
Vol 09 (06) ◽  
pp. 1950049
Author(s):  
Liang Shi ◽  
Cheng Liu ◽  
Huaiwu Zhang
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Microwave Dielectric Properties ◽  
Grain Morphology ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Trigonal System ◽  
C Value

Low temperature sintered Ce2Zr3([Formula: see text][Formula: see text][Formula: see text] (marked as CZMW) ceramics were synthesized via the conventional solid-state reaction method. X-ray diffraction results showed that the CZMW ceramics belonged to a Trigonal system with R-3C space group, and without any impure phase formation. The experimental facts revealed that the density and grain morphology greatly affected the microwave dielectric properties. The samples sintered at 825∘C exhibited good microwave dielectric properties: [Formula: see text], [Formula: see text][Formula: see text]GHz (at 11.3[Formula: see text]GHz) and a satisfactory [Formula: see text] ([Formula: see text]1.5[Formula: see text]ppm/∘C) value. It is suggested that the CZMW ceramics are suitable for low-temperature co-fired ceramic (LTCC) applications in microwave devices.

Influences of MnCO3 Doping on Processing Parameters and Dielectric Properties of ZnNb2O6 Microwave Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 23-26
Author(s):  
J. Luo ◽  
Z.Y. Pang ◽  
Y.S. Lin ◽  
Zhao Xian Xiong
Keyword(s):  
Dielectric Properties ◽  
Ceramic Body ◽  
Microwave Dielectric Properties ◽  
Microwave Frequency ◽  
Solid State Reaction Method ◽  
Processing Parameters ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Ceramic Microstructure

MnCO3 was added into ZnNb2O6 ceramics to obtain excellent microwave dielectric properties. The samples were prepared by conventional solid-state reaction method. The effects of the amount of MnCO3 on sintering temperatures, ceramic densities and contraction were systematically investigated. The crystalline structure of ceramic body was analyzed by XRD. The ceramic microstructure was observed by SEM. The dielectric properties of ZnNb2O6 ceramics were measured by a vector network analyzer at microwave frequency, which showed: er = 22.65, Q×f = 36700 GHz (loaded value) and tf = -40 ppm/°C.

A new low-loss microwave dielectric ceramic for low temperature cofired ceramic applications

2010 ◽  
Vol 25 (7) ◽  
pp. 1235-1238 ◽  
Author(s):  
Huanfu Zhou ◽  
Xiuli Chen ◽  
Liang Fang ◽  
Dongjin Chu ◽  
Hong Wang
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Dielectric Ceramic ◽  
X Ray ◽  
Microwave Dielectric

A new low sintering temperature microwave dielectric ceramic, Li2ZnTi3O8, was investigated. X-ray diffraction data show that Li2ZnTi3O8 has a cubic structure [P4332(212)] with lattice parameters a = 8.37506 Å, V = 587.44 Å3, and Z = 4 when the sintering temperature is 1050 °C. The Li2ZnTi3O8 ceramic exhibits good microwave dielectric properties with εr about 26.2, Q×f value about 62,000 GHz, and τf about −15 ppm/°C. The addition of BaCu(B2O5) can effectively lower the sintering temperature from 1050 to 900 °C without degrading the microwave dielectric properties. Compatibility with Ag electrode indicates this material can be applied to low temperature cofired ceramic devices.

scholarly journals SINTERING BEHAVIOR AND MICROWAVE DIELECTRIC PROPERTIES OF NOVEL LOW TEMPERATURE FIRING Bi3FeMo2O12 CERAMIC

2011 ◽  
Vol 01 (04) ◽  
pp. 379-382 ◽  
Author(s):  
DI ZHOU ◽  
LI-XIA PANG ◽  
JING GUO ◽  
YING WU ◽  
GAO-QUN ZHANG ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Behavior ◽  
Reaction Method ◽  
Temperature Firing ◽  
Microwave Dielectric ◽  
Dielectric Performance

In the present work, a novel low temperature firing Bi 3 FeMo 2 O 12 ceramic was synthesized via the solid-state reaction method. The monoclinic Bi 3 FeMo 2 O 12 phase can be formed at a low temperature 670°C. A relative density above 96% can be obtained when sintering temperature is above 800°C. The Bi 3 FeMo 2 O 12 ceramic sintered at 845°C for 2 h shows high microwave dielectric performance with a permittivity ~27.2, a Qf value of 14,500 GHz and a temperature coefficient of -80 ppm/°C. It might be a candidate for low temperature co-fired ceramics technology.

Effect of V2O5 and ZnO Additives on the Sintering Temperature and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3) 0.8Ti 0.2]O3-δ Ceramics

2011 ◽  
Vol 239-242 ◽  
pp. 77-80 ◽  
Author(s):  
Ji Hong Liao ◽  
Ying Dai ◽  
Ren Zhou Yang ◽  
Wen Chen
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Behavior ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Diffraction Peaks ◽  
Dielectric Ceramics ◽  
The Relationship

Low-temperature sintered Ca[(Li1/3Nb2/3)0.8Ti0.2]O3-δ (CLNT) microwave dielectric ceramics with V2O5 and ZnO additives were prepared by the conventional solid state reaction method. The sintering behavior and microwave dielectric properties of CLNT ceramics were investigated. The main diffraction peaks of all the specimens sintered at the temperature under 1150◦C split due to the coexistence of the non-stoichiometric phase and stoichiometric phase, which all possess CaTiO3-type perovskite structures. ZnO and V2O5 combined additives lowered the sintering temperature of CLNT ceramics from 1150◦C to 1090◦C. and the Qf values were improved from 18,210 GHz to 20,740 GHz. The CLNT ceramics with 4 wt% ZnO addition sintered at 1090◦C showed good microwave dielectric properties with εr ~39.7, Qf ~20,740 GHz, τf ~8.6 ppm/◦C. The relationship between dielectric properties and the sintering behavior was also discussed.

Preparation and Microwave Dielectric Properties of Ca(Sm0.5Nb0.5)O3 Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1198-1202
Author(s):  
Jia Mao Li ◽  
Tai Qiu
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Cooling Rate ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Process ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Microwave Dielectric

Microstructures and microwave dielectric properties of Ca(Sm0.5Nb0.5)O3 ceramics, prepared by a conventional solid-state reaction method, were systematically investigated by varying calcining temperature, sintering temperature and cooling rate. The XRD result showed that a single Ca(Sm0.5Nb0.5)O3 phase could be synthesized at a calcining temperature of 1200 °C. Optimized combination of microwave dielectric properties of εr = 22.36, Q×f = 18030 GHz and τf = -31.2 ppm/°C was obtained for furnace-cooled Ca(Sm0.5Nb0.5)O3 ceramics sintered at 1550 °C for 4 h. However, some microcracks were found from the microstructures of the furnace-cooled specimens. Further, the Q×f value could be increased by controlling the cooling rate during the sintering process due to the disappearance of microcracks in the final material. With a cooling rate of 2 °C/min, Ca(Sm0.5Nb0.5)O3ceramics exhibited an enhanced Q×f value of 37130 GHz.

scholarly journals The microstructure and dielectric properties of titanium oxide doped with nano CuO

2014 ◽  
Vol 04 (03) ◽  
pp. 1450025 ◽  
Author(s):  
Juan Li ◽  
Renli Fu ◽  
Yue Xu ◽  
Zhenxiao Fu ◽  
Hongjuan Su
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Lattice Vibrations ◽  
Sintering Process ◽  
Conventional Solid State Reaction ◽  
Homogeneous Microstructure ◽  
Microwave Dielectric ◽  
Phonon Lifetime ◽  
Better Than

The TiO 2 ceramics doped with nano CuO were fabricated by the conventional solid-state reaction method. The crystal structure, microstructure, microwave dielectric properties and lattice vibrations of TiO 2 ceramics doped with nano CuO have been investigated. Nano CuO with higher sintering capability worked as flux former and effectively improved the sintering process of TiO 2 ceramics. The microwave dielectric properties of TiO 2 doped with nano CuO were much better than that doped with micron CuO at the same doping content. Raman spectra showed that the full width at half maximum of Eg mode of TiO 2 doped with micron CuO was larger than nano CuO doped ones, which indicated a poor crystalline and a short phonon lifetime. TiO 2 doped with 1 wt.% nano CuO , sintered at 950°C for 2 h had compact and homogeneous microstructure and possessed the following dielectric properties: εr = 106, Q × f = 24808, τf = 371 ppm/°C.

Effect of CuO-Bi2O3 Co-Doping on Microwave Dielectric Properties of Ba4Sm9.33Ti18O54 Ceramics

2011 ◽  
Vol 197-198 ◽  
pp. 548-551
Author(s):  
Zhi Lan Tang ◽  
Chun Ying Shen ◽  
Zhao Xi Li ◽  
Jian Yang ◽  
Tai Qiu
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Conventional Solid State Reaction ◽  
Co Doping ◽  
Microwave Dielectric ◽  
Bst Ceramics ◽  
Quality Factor Q

Ba4Sm9.33Ti18O54(BST) ceramics were prepared by conventional solid-state reaction method. The effect of CuO-Bi2O3co-doping on the sintering behavior and microwave dielectric properties of BST ceramics has been investigated. The results indicated that when the total addition of CuO-Bi2O3doping agent was 1.0wt%, the sintering temperature of BST ceramics was reduced to 1240°C as a result of liquid-phase sintering effect derived from CuBi2O4. When the total addition of CuO-Bi2O3was fixed at 1.0wt%, the microwave dielelctric properties of BST were improved by adjusting the mass percentage of Bi2O3. With the increase of Bi2O3amount from 20wt% to 80wt%, the dielectric constant (εr) decreased, the quality factor (Q•f) increased and the temperature coefficient of resonant frequency (τf) shifted from negative value to positive value. The excellent microwave dielectric properties of εr=82.51, Q•f=7878GHz and τf=+6.02ppm/ were obtained for the sample with Bi2O3amount of 80wt% when sintered at 1240°C for 3h.

scholarly journals Chemical synthesis of SmAlO3 by stearic acid route: structure, morphology and microwave dielectric properties

2020 ◽  
Author(s):  
J.M. Li ◽  
Chuimin Zhang ◽  
Hui Liu ◽  
Tai Qiu ◽  
Chuangang Fan
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Stearic Acid ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Frequencies

Abstract A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through spontaneously combusting stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and electron microscopy transmission (TEM) to analyze the phase composition and microstructure. The dielectric characteristics of SmAlO3 microwave ceramics using the as-obtained products as original materials were also studied. Comparing with conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 °C. Large size sheet structure was composed of a number of micro/nano-scale crystallites that were almost irregular in shape due to the mutual growth and overlapped shape of adjacent grains. The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 °C for 4 h due to good sintering activity of the as-synthesized powders. In addition, desired dielectric properties at microwave frequencies (dielectric constant εr = 20.22, quality factor Q·f = 74110 GHz, and temperature coefficient of resonant frequency TCf = -74.6 ppm/°C) were achieved.

scholarly journals Preparation, crystal structure, and dielectric characterization of Li2W2O7 ceramic at RF and microwave frequency range

2017 ◽  
Vol 07 (01) ◽  
pp. 1720001 ◽  
Author(s):  
Jinwu Chen ◽  
Chunchun Li ◽  
Dan Wang ◽  
Huaicheng Xiang ◽  
Liang Fang
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Microwave Frequency ◽  
Solid State Reaction Method ◽  
Frequency Range ◽  
Conventional Solid State Reaction ◽  
Dielectric Characterization ◽  
Microwave Dielectric

Single phase Li2W2O7 with anorthic structure was prepared by the conventional solid-state reaction method at 550[Formula: see text]C and the anorthic structure was stable up to 660[Formula: see text]C. The dielectric properties at radio frequency (RF) and microwave frequency range were characterized. The sample sintered at 640[Formula: see text]C exhibited the optimum microwave dielectric properties with a relative permittivity of 12.2, a quality factor value of 17,700[Formula: see text]GHz (at 9.8[Formula: see text]GHz), and a temperature coefficient of the resonant frequency of [Formula: see text]232[Formula: see text]ppm/[Formula: see text]C as well as a high relative density [Formula: see text]94.1%. Chemical compatibility measurement indicated Li2W2O7 did not react with aluminum electrodes when sintered at 640[Formula: see text]C for 4[Formula: see text]h.

Structural Evolution and Microwave Dielectric Properties of Ba(Co1/3(Nb1-xW5x/6)2/3)O3 Ceramics

2018 ◽  
Vol 281 ◽  
pp. 585-590
Author(s):  
Zhe Fei Wang ◽  
Chen Yao Zhai ◽  
Xu Hong Wang
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Structural Evolution ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

Ba(Co1/3(Nb1-xW5x/6)2/3)O3 (0<x≤0.05) (BCWN) microwave dielectric ceramics have been prepared by solid-state reaction method. The microstructure and microwave dielectric properties of BCWN ceramics were investigated systematically in this paper. The results show that the sintering temperature decreases with the substitution of W6+. The Ba(Co1/3(Nb1-xW5x/6)2/3)O3 solid solution is formed with the small substitution of W6+ (x≤0.01). With the increase of x, the impurity phase BaWO4 occurrs and the grains become less homogeneous. Combined with the analysis of X-Ray Diffraction, the cation ordering degree on B-site increases in the sample of x=0.01, which leads to the decrease of the dielectric loss. However, the second phase BaWO4 inhibits the formation of the ordered structure with the reduction of sinterability. Due to the formation of BaWO4, the values of εr and τf of all samples decrease subsequently. The optimized microwave dielectric properties of Ba(Co1/3(Nb1-xW5x/6)2/3)O3 ceramics were obtained in the samples of x=0.01: εr=33.8, Q×f =110761 GHz, τf = -17 ppm/°C.

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