Crystal Structure and Infrared Reflection Spectra of SrLn2Al2O7(Ln = La, Nd, Sm) Microwave Dielectric Ceramics

2014 ◽  
Vol 12 ◽  
pp. E33-E40 ◽  
Author(s):  
Lei Yi ◽  
Xiao Qiang Liu ◽  
Xiang Ming Chen
Keyword(s):  
Crystal Structure ◽  
Reflection Spectra ◽  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Infrared Reflection ◽  
Dielectric Ceramics

Preparation, Performances and Reaction Process of NiZrNb2O8 Microwave Dielectric Ceramics

2018 ◽  
Vol 281 ◽  
pp. 591-597
Author(s):  
Meng Juan Wu ◽  
Ying Chun Zhang ◽  
Jun Dan Chen ◽  
Yun Zhang
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Raw Materials ◽  
Sem Analysis ◽  
Reaction Process ◽  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Potential Applications ◽  
Dielectric Ceramics

Microwave dielectric ceramics have great potential applications in the fields of modern communication technology. However, the effects of processing of solid reaction on the crystal structure and properties of NiZrNb2O8 has not been reported. In this paper, the NiZrNb2O8 ceramic was prepared using different raw materials. The solid state reaction process, crystal structure, and dielectric properties of the NiZrNb2O8 ceramics were investigated. The X-ray diffractometer (XRD) results showed that the solid state reaction of NiZrNb2O8 could be divided into two steps using NiO, ZrO2 and Nb2O6 as raw materials. Scanning electron microscope (SEM) analysis results showed that the surface of NiZrNb2O8 prepared from NiNb2O6 and ZrO2 was more compact. The optimal density of the samples reached 99.28% of the theoretical value. And the dielectric constant (εr), quality factor (Q×f), temperature coefficient of resonant (τf) reached 23.6, 37237 GHz, -7.796 ppm/°C, respectively.

Structure and Microwave Dielectric Properties of (Ca0.9375Sr0.0625)0.25 (Li0.5Sm0.5)0.75TiO3 Ceramics with B2O3-CuO Sintering Aids

2011 ◽  
Vol 284-286 ◽  
pp. 1442-1446
Author(s):  
Yue Ming Li ◽  
Zong Yang Shen ◽  
Zhu Mei Wang ◽  
Hua Zhang ◽  
Yan Hong ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramics ◽  
Sintering Aids ◽  
Oxide Mixture ◽  
High Permittivity ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

The B2O3-CuO oxide mixture (abbreviated as BC) was selected to lower the sintering temperature of (Ca0.9375Sr0.0625)0.25(Li0.5Sm0.5)0.75TiO3 (abbreviated as CSLST) microwave dielectric ceramics by solid sate reaction technique. The effects of BC doping amounts on the crystal structure, microstructure and microwave dielectric properties of the ceramics were investigated. For the ceramic sample with the composition of CSLST + 5 wt% BC, its sintering temperature was reduced to 1000 °C as compared to 1200 °C for pure CSLST. In addition to the obtained good microwave dielectric properties as follows: εr = 80.4, Q×f = 1380 GHz, τf = -32.89 ×10-6/°C, this ceramic was a desirable high-permittivity microwave dielectric candidate for low-temperature cofired ceramic (LTCC) applications.

Crystal Structure of Dielectric Ceramics in the La(Mg0.5Ti0.5)O3–BaTiO3 System

2002 ◽  
Vol 17 (5) ◽  
pp. 1112-1117 ◽  
Author(s):  
M. Avdeev ◽  
M. P. Seabra ◽  
V. M. Ferreira
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Structural Changes ◽  
Rietveld Method ◽  
Cation Ordering ◽  
Microwave Dielectric Ceramics ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

The crystal structure of microwave dielectric ceramics in the (1 − x)La(Mg0.5Ti0.5)O3 (LMT)–xBaTiO3 (BT) (0 ≤ x ≤ 0.9) system has been refined by Rietveld method using x-ray powder diffraction data. LMT and BT were found to form a solid solution in the whole compositional range. The increase of BaTiO3 content results in the following sequence of structure transformations of those solid solutions: P21/n (a−a−c+, B-site ordered) → Pbnm (a−a−c+) → I4/mcm (a0a0c−) → Pm3m (a0a0a0). These structural changes are related to the disappearance of B-site cation ordering (x > 0.1), in-phase tilting (x > 0.3), and antiphase tilting (x > 0.5), respectively.

Microwave Dielectric Properties of Ca1-x(Li1/2Sm1/2)xTiO3 Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 238-241 ◽  
Author(s):  
Yue Ming Li ◽  
Ting Ting Song ◽  
Fei Hu ◽  
Run Hua Liao ◽  
Bin Zhang
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramics ◽  
Fabrication Technique ◽  
Microwave Dielectric ◽  
Polarizability Effect ◽  
Orthorhombic Perovskite ◽  
Dielectric Ceramics ◽  
A Site

Ca1-x(Li1/2Sm1/2)xTiO3 microwave dielectric ceramics in the x range of 0.70 ~ 0.80 were prepared by conventional ceramics fabrication technique. The crystal structure, microstructure and microwave dielectric properties were investigated. The results showed that a single orthorhombic perovskite structure formed within this x range, and the substitution of (Li1/2Sm1/2)2+ ion for Ca2+ ion in A-site has a significant influence on the microwave dielectric properties of the ceramics. With the increase of substitution of (Li1/2Sm1/2)2+ ion with 0.75, the temperature coefficient of resonant frequency τf reaches zero, and it could be attributed that the Sm and Li have a polarizability effect according to its microstructure. The Ca0.25(Li1/2Sm1/2)0.75TiO3 ceramic had a good performance with microwave dielectric properties of τf = 0 ppm/°C, εr = 105.83, and Qf = 3170 GHz.

Crystal structure of La(Mg2/3M1/3)O3 (M=Nb,Ta) microwave dielectric ceramics

1999 ◽  
Vol 38 (4) ◽  
pp. 294-299 ◽  
Author(s):  
Jeong-Seog Kim ◽  
Chae-Il Cheon ◽  
Hyun-Ju Kang ◽  
Hae-Seop Shim ◽  
Chang-Hee Lee ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

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.

Study on the (1-x)(Mg0.7Zn0.3)TiO3-x(Ca0.61Nd0.26)TiO3 Microwave Dielectric Ceramics

2010 ◽  
Vol 25 (3) ◽  
pp. 332-336
Author(s):  
Zheng-Dong LU ◽  
Chun-Ying SHEN ◽  
Liang LI ◽  
Jian YANG ◽  
Tai QIU
Keyword(s):  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Dielectric Ceramics
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