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Improved High‐ Q Microwave Dielectric Ceramics in CuO ‐Doped BaTi 4 O 9 – BaZn 2 Ti 4 O 11 System
Author(s) -
Yu Sheng Quan,
Tang Bin,
Zhang Xiao,
Zhang Shu Ren,
Zhou Xiao Hua
Publication year - 2012
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.1551-2916.2012.05086.x
Subject(s) - sintering , materials science , analytical chemistry (journal) , dielectric , ceramic , temperature coefficient , doping , mineralogy , nuclear chemistry , chemistry , composite material , chromatography , optoelectronics
To improve the microwave dielectric properties, CuO was doped into composite ceramics BaTi 4 O 9 – BaZn 2 Ti 4 O 11 by the solid‐state reaction. CuO worked as flux former and caused the liquid‐phase sintering mechanism, which effectively improved the densification process and lowered the sintering temperature by nearly 100°C. Moreover, Cu 2+ substituted for Zn 2+ sites in BaZn 2 Ti 4 O 11 phase, which led to the increase of BaZn 2 Ti 4 O 11 phase and the reduction of lattice parameters of BaZn 2 Ti 4 O 11 phase, and both these two results had the positive effect on the dielectric properties, especially the Q × f value. As increasing CuO content from 0.0 to 3.0 wt%, the dielectric constant ( ε r ) increased from 35.5 to 36.5, the Q × f value increased first from 49 100 GHz to the peak value 62 600 GHz (1.0 wt% CuO ) and thereafter decreased to 31 900 GHz, and the temperature coefficient of resonant frequency ( τ f ) kept in a low value as <2.0 wt% CuO was added. At last, 0.85 BaTi 4 O 9 –0.15 BaZn 2 Ti 4 O 11 ceramics with 1.0 wt% CuO sintered at 1150°C for 3 h showed excellent microwave dielectric properties: the high ε r = 36.4, the high Q × f = 62 600 GHz and the near‐zero τ f = +0.2 ppm/°C.