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Low‐Temperature Sintering and Microwave Dielectric Properties of Ba 5 Nb 4 O 15 –BaWO 4 Composite Ceramics for LTCC Applications
Author(s) -
Zhuang Hao,
Yue Zhenxing,
Zhao Fei,
Li Longtu
Publication year - 2008
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.1551-2916.2008.02670.x
Subject(s) - materials science , cofiring , sintering , ceramic , dielectric , temperature coefficient , composite number , analytical chemistry (journal) , mineralogy , composite material , chemistry , optoelectronics , chromatography , combustion
Low‐temperature‐sintered composite ceramics in Ba 5 Nb 4 O 15 –BaWO 4 system were prepared by cofiring mixtures of Ba 5 Nb 4 O 15 and BaWO 4 powders. Thermo‐mechanical analysis indicated that a small amount of B 2 O 3 addition significantly promoted the densification process and lowered the sintering temperature to ∼900°C. X‐ray diffraction analysis revealed that Ba 5 Nb 4 O 15 and BaWO 4 coexisted in the sintered ceramics. With increasing B 2 O 3 content, a secondary phase, BaNb 2 O 6 , appeared which affects the microwave dielectric properties. Microwave dielectric properties of the aforementioned compositions were as follows: dielectric constant of 16.8–19.2, Q × f values of 33 900–50 300 GHz, and a temperature coefficient of the resonant frequency of −3.4 to −8.6 ppm/°C. The chemical compatibility of BNW6502 ceramics with silver during the cofiring process has also been investigated, and no evidence of chemical reaction between Ag and ceramics was observed, indicating that the as‐prepared composite ceramics are suitable for low‐temperature cofired ceramics applications.