Structure and Microwave Dielectric Properties of Hexagonal Ba[Ti^sub 1-x^(Ni^sub 1/2^W^sub 1/2^)^sub x^]O^sub 3^ Ceramics

Microwave dielectric ceramics with the composition of ... (x=0.4-0.6) were prepared by a solid-state reaction method. The evolution of the crystalline phases was investigated by X-ray powder diffraction analysis. A cubic-to-hexagonal phase transition occurred between 1000... and 1300...C. The phase...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2007-08, Vol.90 (8), p.2461
Main Authors: Zhao, Fei, Yue, Zhenxing, Pei, Jing, Zhuang, Hao
Format: Article
Language:English
Subjects:
Ceramics
Dielectrics
Diffraction
Phase transitions
Online Access:Get full text
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Summary:Microwave dielectric ceramics with the composition of ... (x=0.4-0.6) were prepared by a solid-state reaction method. The evolution of the crystalline phases was investigated by X-ray powder diffraction analysis. A cubic-to-hexagonal phase transition occurred between 1000... and 1300...C. The phase transition is irreversible; thus, the hexagonal phase remains stable at room temperature. The X-ray powder diffraction data for x=0.5 were refined using the Rietveld method. It was identified as a h-...-type hexagonal perovksite with the space group of .../mmc. It also reveals that random occupancy of ... and ... ions occurs in the B-site substructures, whereas ... ions exclusively occupy the octahedral site in the corner-sharing octahedron. The dielectric properties of dense-sintered ceramics were characterized at microwave frequencies. With an increase in x from 0.4 to 0.6, the Q x f value increased from 26 700 to 42 000 GHz, whereas ... decreased from 29.8 to 20.0, and ...from +6.5 to -9.9 ppm/...C. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0002-7820
1551-2916