Role of Bi{sub 2}O{sub 3} in optimizing the dielectric properties of Ba{sub 4.5}Nd{sub 9}Ti{sub 18}O{sub 54} based microwave ceramics
- Department of Ceramics, ``Jozef Stefan`` Institute, University of Ljubljana, Ljubljana (Slovenia)
Small additions of Bi{sub 2}O{sub 3} or bismuth titanate improve the dielectric properties of Ba{sub 4.5}Nd{sub 9}Ti{sub 18}O{sub 54} at microwave frequencies. It was found that Bi{sup 3+} can replace Nd{sup 3+} up to 15 mol {percent}, the limiting composition of solid solution being Ba{sub 4.5}(Nd{sub 0.85}Bi{sub 0.15}){sub 9}Ti{sub 18}O{sub 54}. At the solid solution limit the temperature coefficient of resonant frequency attains its minimum value. The modified ceramic is distinguished by high permittivity of 99 and a {ital Q}-value of 5500. The temperature coefficient of resonant frequency is low, 15 ppm/K. After exceeding the solid solubility limit, additional Bi{sub 2}O{sub 3} concentrates as a Bi-rich phase at the grain boundaries, causing considerable reduction of the {ital Q}-value and an increase of {tau}{sub {ital f}}. {copyright} {ital 1996 Materials Research Society.}
- OSTI ID:
- 280126
- Journal Information:
- Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 4 Vol. 11; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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