Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3−δ microwave dielectric ceramic

2017 ◽  
Vol 31 (27) ◽  
pp. 1750192
Author(s):  
Mingzhe Hu ◽  
Huanghe Wei ◽  
Lihua Xiao ◽  
Kesheng Zhang ◽  
Yongde Hao
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
Microwave Ceramics ◽  
Dielectric Ceramic ◽  
Structure Transition ◽  
Microwave Dielectric ◽  
Dielectric Devices

The crystal structure and dielectric properties of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the [Formula: see text]-site order–disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramic can be compensated and the optimal microwave dielectric properties can reach [Formula: see text] = 25.66, [Formula: see text] = 18,894 GHz and TCF = −6.3 ppm/[Formula: see text]C when sintered at 1170[Formula: see text]C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.

Studies on Structural, Microwave Dielectric Properties, and Low-Temperature Sintering of 1.52Li2O-0.36Nb2O5-1.34TiO2 Ceramic

2012 ◽  
Vol 512-515 ◽  
pp. 1226-1230
Author(s):  
Qun Zeng ◽  
Yong Heng Zhou
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
Low Temperature Sintering ◽  
Dielectric Ceramic ◽  
Microwave Dielectric ◽  
M Phase ◽  
Two Phases

The structure, microwave dielectric properties and low-temperature sintering of a new Li2O-Nb2O5-TiO2 system ceramic with the Li2O: Nb2O5: TiO2 mole ratio of 1.52: 0.36: 1.34 have been investigated in this study. The 1.52Li2O-0.36Nb2O5-1.34TiO2 (LNT) ceramic is composed of two phases, the “M-Phase” and Li2TiO3 solid solution (Li2TiO3ss) phase. This new microwave dielectric ceramic has low intrinsic sintering temperature ( ~ 1100 oC ) and good microwave dielectric properties of middle permittivity (εr ~38.6), high Q×f value up to 7712 GHz, and near zero τf value (~ 4.64 ppm/oC). In addition, the sintering temperature of the LNT ceramics could be lowered down effectively from 1100 oC to 900 oC by adding 1 wt.% B2O3. Good microwave dielectric properties of εr = 42.5, Q*f =6819 GHz and τf = 2.7 ppm/oC could be obtained at 900 oC, which indicate the ceramics would be promising candidates for low-temperature co-fired ceramics (LTCC) applications.

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.

Effects of Ta5+ Substitution on Structure Transition and Microwave Dielectric Properties of Zn(Nb1-xTax)2O6 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 265-268 ◽  
Author(s):  
Ying Chun Zhang ◽  
Xiu Hong Yang ◽  
Zhen Xing Yue ◽  
Fei Zhao ◽  
Long Tu Li
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Network Analyzer ◽  
Microwave Dielectric Ceramics ◽  
Zero Temperature ◽  
Quality Factors ◽  
Structure Transition ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

The crystal structure, phase relation, microstructure and dielectric properties of microwave dielectric ceramics comprised of Zn(Nb1-xTax)2O6 were investigated systematically using XRD, SEM and a network analyzer in this study. XRD results show that the Zn(Nb1-xTax)2O6 ceramics have the orthorhombic for all x values. However, two kinds of solid solutions phase regions based on columbite structure and ZnTa2O6 structure were observed. SEM results show that the growth of grains is restrained with increase of Ta content in Zn(Nb1-xTax)2O6 ceramics. The dielectric properties exhibited a significant dependence on the crystal structure and compositions of the ceramics. The dielectric constant (εr) of Zn(Nb1-xTax)2O6 ceramics increased with increasing Ta content. However, the quality factors (Q×f) of this system show a different trend, and decrease with increasing Ta content. At x=0.65, a zero temperature coefficient of resonant frequency ( τ f) can be realized in Zn(Nb1-xTax)2O6 ceramics system.

Sintering behavior and dielectric properties of Bi3+-substituted Nd(Zn0.5Ti0.5)O3 microwave ceramics

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550233 ◽  
Author(s):  
Mingzhe Hu ◽  
Zhao Ding ◽  
Gang Xiong ◽  
Denghui Ji ◽  
Kesheng Zhang
Keyword(s):  
Dielectric Properties ◽  
Volume Fraction ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Microwave Ceramics ◽  
Microwave Dielectric ◽  
Bi Doping ◽  
Sintering Conditions

The sintering behavior and dielectric properties of Bi[Formula: see text]-substituted Nd(Zn[Formula: see text]Ti[Formula: see text]O3 (abbreviated as NZT) microwave ceramics (Nd[Formula: see text]Bi[Formula: see text])(Zn[Formula: see text]Ti[Formula: see text])O3 [Formula: see text] (abbreviated as NBZT) are investigated. XRD results reveal the formation of single perovskite solid solutions for [Formula: see text] samples. For [Formula: see text] samples, pyrochlore phase begins to segregate from the perovskite phase and its volume fraction increases with [Formula: see text]. B-site Zn[Formula: see text]/Ti[Formula: see text] 1:1 long range order (LRO) is detected by Raman Spectroscopy. The degree of LRO varies as a function of sintering conditions and chemical composition. The microwave dielectric properties of the composition are measured. By substituting Bi[Formula: see text] for Nd[Formula: see text], the temperature coefficient of resonant frequency [Formula: see text] tunes toward zero, however, the microwave quality factor, [Formula: see text] deteriorates. For [Formula: see text], [Formula: see text] reaches a minimum value of [Formula: see text] with relative permittivity of [Formula: see text] and [Formula: see text], respectively. The effect of Bi-doping on the [Formula: see text] value is discussed.

Low Temperature Co-Fired ZnNb2O6 Dielectric Ceramic Doped by B2O3

2016 ◽  
Vol 849 ◽  
pp. 209-215 ◽  
Author(s):  
Jian Yang ◽  
Ji Kang Yan ◽  
Jing Hong Du ◽  
Fang Chun Yan ◽  
Kun Yong Kang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Ionic Diffusion ◽  
Microwave Dielectric Ceramic ◽  
Dielectric Ceramic ◽  
Microwave Dielectric ◽  
Microstructure Density ◽  
Activation Energy Of Diffusion

To lower the sintering temperature of ZnNb2O6 microwave dielectric ceramic, ZnNb2O6 doped with B2O3 were prepared by the traditional solid state reaction method. The effects of the amount of B2O3 (0.25-5.0wt.%) on the microstructure, density and electrical performances were investigated. The results show that a pure columbite ZnNb2O6 phase was obtained for all B2O3-doped ceramics. The microwave dielectric properties reached the maximum values of εr = 24.1, Q×f = 19502 GHz, τf = -52.19 ppm/°C for 1wt% B2O3-doped ZnNb2O6 ceramic sintered at 1050 °C for 4 h. All of evidences suggest that the enhancement of microwave dielectric properties is due to the enhanced ions-energy and ionic diffusion with the increase of sintering temperature. Furthermore, B2O3 doping can generate liquid phase and reduce the activation energy of diffusion to promote the materials sintering.

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