The Effect of LnAlO3(Ln=Nd,Sm) Additives on the Microwave Dielectric Properties of BaO-Nd2O3-5TiO2 Ceramics

2014 ◽  
Vol 633 ◽  
pp. 340-343
Author(s):  
Yue Xu ◽  
Ren Li Fu ◽  
Juan Li ◽  
Zhen Xiao Fu ◽  
Hong Juan Su
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Phase Evolution ◽  
Densification Behavior ◽  
Grain Sizes ◽  
Microwave Dielectric ◽  
Linear Behaviour ◽  
Columnar Grain

The effect of LnAlO3 (Ln = Nd, Sm) additives on the densification, phase evolution, microstructure and dielectric properties of BaO-Nd2O3-5TiO2 (BNT5) ceramics was investigated. The LnAlO3 (Ln = Nd, Sm) had greatly influence on the densification behavior of the BNT5 ceramics and the grain sizes of BNT5 ceramics could be effectively refined by LnAlO3 additive. The microstructure of BNT5 ceramics was transformed from quasi-rectangular grain to columnar grain while the content of LnAlO3 was increasing. The dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) were reduced with the increase of LnAlO3 content, whereas the Q×f values showed a non-linear behaviour with LnAlO3 content increasing. The BNT5 ceramics doped with 12.5 wt% SmAlO3, sintered at 1320°C for 4 h, had the excellent dielectric properties of εr = 62.78, Q×f = 11108 GHz and τf = -1.55 ppm/°.

Microwave dielectric properties of Ca[(Li1/3Nb2/3)1−xMx]O3−δ (M = Sn, Ti) ceramics

1999 ◽  
Vol 14 (9) ◽  
pp. 3567-3570 ◽  
Author(s):  
Ji-Won Choi ◽  
Chong-Yun Kang ◽  
Seok-Jin Yoon ◽  
Hyun-Jai Kim ◽  
Hyung-Jin Jung ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Multiphase Materials ◽  
Microwave Dielectric ◽  
Orthorhombic Perovskite

The microwave dielectric properties of Ca[(Li1/3Nb2/3)1−xMx]O3−δ (M = Sn, Ti, 0 ≤ x ≤ 0.5) ceramics were investigated. In general, the ceramics prepared were multiphase materials. However, single-phase specimens having orthorhombic perovskite structure similar to CaTiO3 could be obtained in the vicinity of Sn = 0.2 to 0.3, and Ti = 0.2. As Sn concentration increased, the dielectric constant (εr) decreased and the quality factor (Q) significantly increased within the limited Sn concentration. As Ti concentration increased, the dielectric constant (εr) increased, the quality factor (Q) decreased, and the temperature coefficient of resonant frequency (τf) changed from a negative to positive value. The temperature coefficient of resonant frequency of 0 ppm/°C was realized at Ti = 0.2. The Q · fo value and εr for this composition were found to be 26100 GHz and 38.6, respectively.

Dielectric properties of La-substituted Pb0.5Ca0.5[(Mg1/3Nb2/3)0.5Ti0.5]O3 ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2053-2056
Author(s):  
X. J. Lu ◽  
X. M. Chen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Microwave Dielectric Properties ◽  
Present Approach ◽  
Calculated Temperature ◽  
Microwave Dielectric ◽  
La Substitution ◽  
Dielectric Ceramics

Modification of Pb0.5Ca0.5[(Mg1/3Nb2/3)0.5Ti0.5]O3 dielectric ceramics was performed by up to 20 mol% La substitution for Pb and Ca. The temperature coefficient of dielectric constant was significantly reduced by the present approach, while an increased Qf factor was achieved. Good microwave dielectric properties were obtained in a composition Pb0.425Ca0.425La0.1[(Mg1/3Nb2/3)0.5Ti0.5]O3: ε = 125; Qf = 3150 GHz; calculated temperature coefficient of resonant frequency δf = +253 ppm/°C.

Effects of CuO and V2O5 Addition on Sintering Behavior and Microwave Dielectric Properties of (1-x)Ca2P2O7-xTiO2

2007 ◽  
Vol 336-338 ◽  
pp. 279-282
Author(s):  
In Sun Cho ◽  
Sang Gu Kang ◽  
Dong Wan Kim ◽  
Kug Sun Hong
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Microwave Dielectric

The effects of CuO and V2O5 addition on sintering behaviors and microwave dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics were investigated. With CuO and V2O5 addition, the sintering temperature of 0.7Ca2P2O7-0.3TiO2 can be effectively reduced from 1150 to 950oC. The dielectric constant of the low fired 0.7Ca2P2O7-0.3TiO2 ceramics was not significantly changed while the quality factor was affected by additives. The temperature coefficient of resonant frequency value was increased in negative value with the additive contents. V2O5 and CuO additives effectively improved the densification and dielectric properties of 0.7Ca2P2O7-0.3TiO2 ceramics. The correlation between the phase constituents and the dielectric properties was investigated with additive contents.

Shifting τf Value of (Mg0.95Co0.05)TiO3 Ceramics by Ca0.61Nd0.78/3TiO3 Addition

2013 ◽  
Vol 807-809 ◽  
pp. 2703-2706
Author(s):  
Ping Cheng Chen ◽  
Chung Long Pan ◽  
Wei Cheng Lin ◽  
Chun Hsu Shen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Significant Role ◽  
Microwave Dielectric Properties ◽  
Dielectric Measurement ◽  
Zero Temperature ◽  
Microwave Dielectric

Modification of (Mg0.95Co0.05)TiO3ceramics by Ca0.61Nd0.78/3TiO3addition was investigated. The Ca0.61Nd0.78/3TiO3content plays a significant role in improving the dielectric properties. Microwave dielectric measurement showed an increase in dielectric constant (εr) and temperature coefficient of the resonant frequency (τf) and a decrease inQvalue with increasing Ca0.61Nd0.78/3TiO3content. By properly adjusting the Ca0.61Nd0.78/3TiO3content, zero temperature coefficient of resonate frequencyτfcan also be obtained. It becomes more promising in the application of wireless system.At 1375°C, the 0.85(Mg0.95Co0.05)TiO3-0.15Ca0.61Nd0.78/3TiO3ceramics possesses excellent microwave dielectric properties: a dielectric constant εr of 24.37, aQfvalue of 66200 ( at 7 GHz ) and a τf value of-1.4 ppm/°C.

INFLUENCE OF n ON STRUCTURE AND MICROWAVE DIELECTRIC PROPERTIES OF SOME AnBn - 1O3n PEROVSKITES

2011 ◽  
Vol 01 (01) ◽  
pp. 135-140
Author(s):  
LIANG FANG ◽  
ZHAO YANG ◽  
HUI ZHANG ◽  
CHUNCHUN LI ◽  
HEPING SU
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
General Formula ◽  
Microwave Dielectric Properties ◽  
Structure And Properties ◽  
Quality Factors ◽  
Microwave Dielectric

Two series of B-site deficient perovskites Ba 5+m Ti m Nb 4 O 15+3m(m = 1, 2, 3) and Sr 3+m LaTi m Nb 3 O 12+3m(m = 0, 1, 2) with the general formula A n B n - 1 O 3n(n = 4 - 8; A = Ba , Sr , La ; B = Nb , Ti ) have been synthesized, and their structure and microwave dielectric properties have been investigated. The effects of n (number of octahedra layers within a perovskite blocks) on structure and properties are investigated. The values of dielectric constant εr and temperature coefficient of resonant frequency τf gradually increase, but quality factors Q × f values significantly decreases as the values of n increase.

DIELECTRIC PROPERTIES OF Ca(1-x)ZnxLa4Ti5O17 CERAMICS AT MICROWAVE FREQUENCIES

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1179-1184 ◽  
Author(s):  
Yih-Chien Chen ◽  
Jian-Min Tsai
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Maximum Density ◽  
Zero Temperature ◽  
Microwave Frequencies ◽  
Microwave Dielectric ◽  
Diffraction Peaks ◽  
Quality Factor Q

In this paper, the microwave dielectric properties of Ca (1- x ) Zn x La 4 Ti 5 O 17 ceramics have been studied. The diffraction peaks of Ca (1- x ) Zn x La 4 Ti 5 O 17 ceramics shift to higher angles as x increases from 0 to 0.01 and nearly unchanged with x increasing from 0.01 to 0.03. A maximum density of dielectric constant value of 57 and a quality factor ( Q × f ) of 15000 GHz can be obtained for Ca 0.99 Zn 0.01 La 4 Ti 5 O 17 ceramic sintered at 1450°C for 4h. A near-zero temperature coefficient of resonant frequency (τ f ) of -8.1 ppm/°C can be obtained for Ca 0.99 Zn 0.01 La 4 Ti 5 O 17 ceramic sintered at 1450°C for 4h.

Effects of Mg2+ on Microstructure and Microwave Dielectric Properties of La2/3TiO3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 35-38 ◽  
Author(s):  
Ai Min Yang ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Microwave Dielectric ◽  
Maximum Permittivity

(1-x)La2/3TiO3-xLa(Mg1/2Ti1/2)O3 ceramics with x ranging from 0.01 to 0.3 were prepared by the conventional solid-state reaction method. Microstructure and microwave dielectric properties were studied. The perovskite compound La2/3TiO3 is stabilized when x = 0.1. The content of La2/3TiO3 increases with increasing x from 0.01 to 0.1, and thereafter decreases when x > 0.1. The same tendency was also observed on measuring the dielectric constant, temperature coefficient of resonant frequency and Q× ƒ. A maximum permittivity of 77.35 was achieved with these stabilized La2/3TiO3 ceramics. Close to zero τf value (1 ppm/°C) was obtained at x=0.3, but its Q× ƒ value was relative low.

Micr owave Dielectric Properties of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 Ceramics System

2003 ◽  
Vol 783 ◽  
Author(s):  
Cheng-Liang Huang ◽  
Yuan-Bin Chen ◽  
Ching-Wen Lo
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Resonant Frequency ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Compositional Range ◽  
Microwave Dielectric

ABSTRACTThe microwave dielectric properties of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 (0.1≤x≤1.0) have been investigated. The system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 152 to 27 as x varies from 0.1 to 1.0. In the (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 system, the microwave dielectric properties can be effectively controlled by varying the x value. A maximum quality factor Qxf=43000GHz (where f is the resonant frequency) was achieved for samples with x=0.9, although the dielectric properties varied with sintering temperature. The Qxf value of (1-x)CaTiO3-xNd(Mg1/2Ti1/2)O3 almost increased up to 1500°C, after which it decreased. At 1400°C, 0.1CaTiO3-0.9Nd(Mg1/2Ti1/2)O3 ceramics gives a dielectric constant εr of 42, a Qxf value of 35000 (GHz) and a τf value of -10 (ppm/°C).

Fabrication of Ba6-3x(Sm0.2Nd0.8)8+2xTi18O54(x=2/3) Ceramics by Solid State Reaction

2007 ◽  
Vol 336-338 ◽  
pp. 258-261
Author(s):  
Yong Zheng ◽  
Wen Lei ◽  
Hai Jian Bu ◽  
Xing Zhong Zhao
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Solid State ◽  
Resonant Frequency ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintered Ceramic ◽  
Temperature Coefficients ◽  
Microwave Dielectric

Effects of calcining and sintering temperatures on the microstructure and the microwave dielectric properties of Ba6-3x(Sm0.2Nd0.8)8+2xTi18O54(x=2/3) ceramics were studied. When the calcining temperature was lower (1373K), the dielectric constant ε and the Qf factor initially increased with increasing sintering temperature, but decreased when sintering temperature was higher than 1603K. As a whole, the temperature coefficients of the resonant frequency τf tended to increase with increasing sintering temperature. The microstructure of the sintered ceramic consisted mainly of columnar and block-shape grains. The grain size increased with increasing sintering temperature. When the calcining temperature was higher (1473K), εr and τf were nearly independent of sintering temperature. The excellent microwave dielectric properties were achieved in the Ba6-3x(Sm0.2Nd0.8)8+2xTi18O54 (x=2/3) ceramic calcined at 1373K and sintered at 1603K for 3 h: ε = 80.8, Qf = 8114 (GHz) and τf = 5.6.

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