Jj. Shyu et Hw. Peng, Crystallization and dielectric properties of SrO-BaO-Nb2O5-GeO2 tungsten-bronze glass-ceramics, J MATER RES, 16(7), 2001, pp. 2057-2063
The crystallization and dielectric properties of SrO-BaO-Nb2O5-GeO2 glass-c
eramics were investigated. One- and two-stage heat-treatment methods were u
sed to convert the parent glass to glass-ceramics. Strontium barium niobate
(SBN) with a tetragonal tungsten-bronze structure formed as the major crys
talline phase. When the crystallizing emperature/time was increased, the se
condary crystalline BaGe2O5 phase coexisted with SBN, BaGe2O5 formed as a s
urface layer grown from the surface into the interior of the sample. The de
ndritic morphology of SBN crystals was examined. The glass-ceramics crystal
lized by two-stage heat treatment have higher dielectric constants than tho
se crystallized by one-stage heat treatment. The highest dielectric constan
t that was obtained in the present glass-ceramics was 320. The glass-cerami
cs showed relaxer-type dielectric behavior.