Cl. Huang et al., The microwave dielectric properties and the microstructures of La2O3-modified BiNbO4 ceramics, JPN J A P 1, 39(6A), 2000, pp. 3506-3510
The microwave dielectric properties and the microstructures of La2O3-modifi
ed BiNbO4 ceramics were investigated. (Bi1-xLax)NbO4 ceramics combined with
orthorhombic and triclinic phases are identified at sintering temperatures
of 920-980 degrees C. The density and grain size of (Bi1-xLax)NbO4 ceramic
s both increase with increasing sintering temperature while both decrease s
lightly with the increase of La2O3 content. The dielectric constant epsilon
(r), the quality factor Q and the temperature coefficient of resonant frequ
ency tf of the ceramics are affected by the La2O3 content and correlated wi
th its microstructure. At a sintering temperature of 920 degrees C and x va
lue of 0.01, (Bi1-xLax)NbO4 ceramics exhibit the microwave dielectric prope
rties of epsilon(r) similar to 43.36, Q x f similar to 10600 (at 7 GHz), an
d tau(f) similar to 2 ppm/degrees C.