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Role of Bi2O3 in optimizing the dielectric properties of Ba4.5Nd9Ti18O54 based microwave ceramics

Published online by Cambridge University Press:  31 January 2011

Matjaž Valant ,
Danilo Suvorov  and
Drago Kolar
Matjaž Valant
Affiliation:
Department of Ceramics, “Jožef Stefan” Institute, University of Ljubljana, Ljubljana, Slovenia
Danilo Suvorov
Affiliation:
Department of Ceramics, “Jožef Stefan” Institute, University of Ljubljana, Ljubljana, Slovenia
Drago Kolar
Affiliation:
Department of Ceramics, “Jožef Stefan” Institute, University of Ljubljana, Ljubljana, Slovenia
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Abstract

Small additions of Bi2O3 or bismuth titanate improve the dielectric properties of Ba4.5Nd9Ti18O54 at microwave frequencies. It was found that Bi3+ can replace Nd3+ up to 15 mol%, the limiting composition of solid solution being Ba4.5(Nd0.85Bi0.15)9Ti18O54. 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 Q-value of 5500. The temperature coefficient of resonant frequency is low, 15 ppm/K. After exceeding the solid solubility limit, additional Bi2O3 concentrates as a Bi-rich phase at the grain boundaries, causing considerable reduction of the Q-value and an increase of τf.

Type
Articles
Information
Journal of Materials Research , Volume 11 , Issue 4 , April 1996 , pp. 928 - 931
Copyright
Copyright © Materials Research Society 1996

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References

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