Synthesis, structure, and characterization of new low-firing microwave dielectric ceramics: (Ca1−3xBi2xΦx)MoO4

2014 ◽  
Vol 2 (35) ◽  
pp. 7364-7372 ◽  
Author(s):  
Jing Guo ◽  
Clive A. Randall ◽  
Gaoqun Zhang ◽  
Di Zhou ◽  
Yuyan Chen ◽  
...  
Keyword(s):  
Solid Solution ◽  
Microwave Dielectric Ceramics ◽  
Local Structures ◽  
Microwave Dielectric ◽  
Dielectric Ceramics ◽  
A Site

A series of A-site defective scheelite (Ca1−3xBi2xΦx)MoO4 compositions were formed as a solid solution, and their local structures indicate that Bi–O polyhedrons become more distorted with x value.

Modification of Ba6-3xSm8+2xTi18O54 (x=2/3)Microwave Dielectric Ceramics by Nd/Bi Co-Substitution on A-Site

2007 ◽  
Vol 280-283 ◽  
pp. 57-60 ◽  
Author(s):  
N. Qin ◽  
X.M. Chen
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Single Phase ◽  
Tungsten Bronze ◽  
Sem Analysis ◽  
Microwave Dielectric Ceramics ◽  
Co Substitution ◽  
Microwave Dielectric ◽  
Dielectric Ceramics ◽  
A Site

Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics were modified by Nd/Bi co-substitution for Sm on A-site. According to XRD and SEM analysis, a single-phase solid solution with new tungsten bronze-type structure was formed in low-Bi-substituted region. Bi was effective on increasing dielectric constant, while led to a decreased Qf value and an increased negative tf. The co-substituting approach exhibited the advantage in improving e and compensating Qf and tf value.

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.

Characterization of Microstructures and Defects in SrSmAlO4-Based Microwave Dielectric Ceramics by TEM

2014 ◽  
Vol 470 (1) ◽  
pp. 117-125 ◽  
Author(s):  
Min Min Mao ◽  
Lei Li ◽  
Yao Wu Zeng ◽  
Xiang Ming Chen
Keyword(s):  
Microwave Dielectric Ceramics ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

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.

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