A novel microwave dielectric ceramic Ca{sub 2}Zn{sub 4}Ti{sub 16}O{sub 38}: Preparation and dielectric properties

A novel microwave dielectric powder with composition of Ca{sub 2}Zn{sub 4}Ti{sub 16}O{sub 38} was synthesized through a citrate sol-gel process. The development of crystalline phases with heat-treating temperature for the gel derived powders was evaluated by using thermo-gravimetric analysis and X-r...

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Bibliographic Details
Published in:Journal of solid state chemistry 2006-06, Vol.179 (6)
Main Authors: Zhao Fei, Yue Zhenxing, Pei Jing, Gui Zhilun, Li Longtu
Format: Article
Language:English
Subjects:
CALCIUM COMPOUNDS
CERAMICS
CRYSTAL STRUCTURE
DIELECTRIC MATERIALS
GHZ RANGE
GRAVIMETRIC ANALYSIS
IMPEDANCE
MATERIALS SCIENCE
MICROWAVE RADIATION
MONOCRYSTALS
OXIDES
PERMITTIVITY
SOL-GEL PROCESS
SPECTROSCOPY
TEMPERATURE RANGE 1000-4000 K
TITANIUM COMPOUNDS
X-RAY DIFFRACTION
ZINC COMPOUNDS
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Summary:A novel microwave dielectric powder with composition of Ca{sub 2}Zn{sub 4}Ti{sub 16}O{sub 38} was synthesized through a citrate sol-gel process. The development of crystalline phases with heat-treating temperature for the gel derived powders was evaluated by using thermo-gravimetric analysis and X-ray powder diffraction analysis techniques. The pure phase of Ca{sub 2}Zn{sub 4}Ti{sub 16}O{sub 38} with crichtonite crystal structure was obtained at relatively low temperature of 1000 deg. C. The synthesized powder has high reactivity and the dense ceramics with single crystalline phase were obtained at low sintering temperature of 1100 deg. C. Impedance spectroscopy and microwave dielectric measurements on sintered samples showed the present compound to be a modest dielectric insulator with excellent dielectric properties of {epsilon} {sub r}{approx}47-49, Qf value {approx}27,800-31,600 GHz and {tau} {sub f}{approx}+45 to +50 ppm/deg. C. It shows comparable microwave dielectric properties to other moderate-permittivity microwave dielectrics, but much lower sintering temperature of 1100 deg. C. - Graphical abstract: XRD patterns for the Ca{sub 2}Zn{sub 4}Ti{sub 16}O{sub 38} precursor powders after calcining at: (a) 600 deg. C, (b) 700 deg. C, (c) 800 deg. C, (d) 900 deg. C, and (e) 1000 deg. C. Display Omitted.
ISSN:0022-4596
1095-726X
DOI:10.1016/j.jssc.2006.03.007