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Phase Formation and Dielectric Characterization of the Bi 2 O 3 –TeO 2 System Prepared in an Oxygen Atmosphere
Author(s) -
Udovic Marko,
Valant Matjaz,
Suvorov Danilo
Publication year - 2004
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2004.00591.x
Subject(s) - oxygen , ceramic , atmosphere (unit) , dielectric , analytical chemistry (journal) , sintering , materials science , permittivity , temperature coefficient , mineralogy , phase (matter) , chemistry , metallurgy , composite material , thermodynamics , organic chemistry , optoelectronics , physics
Solid‐state synthesis of compositions from the Bi 2 O 3 –TeO 2 system show that, under an oxygen atmosphere, Te 4+ oxidizes to Te 6+ and yields four room‐temperature stable compounds: Bi 2 Te 2 O 8 , Bi 2 TeO 6 , Bi 6 Te 2 O 15 , and new a compound with the nominal composition 7Bi 2 O 3 ·2TeO 2 . Dense ceramics can be prepared from all these compounds by sintering between 650° and 800°C under an oxygen atmosphere. The permittivity of these compounds varies from ∼30 to ∼54, the Q × f value from 1.100 to 41.000 GHz (∼5 GHz), and the temperature coefficient of resonant frequency from −43 to −144 ppm/K. Bi 6 Te 2 O 15 and 7Bi 2 O 3 ·2TeO 2 do not react with silver, and, therefore, they have the potential to be used for applications in low‐temperature cofired ceramic (LTCC) technology.