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Effects of Mg Substitution on Microstructures and Microwave Dielectric Properties of Ba(Zn 1/3 Nb 2/3 )O 3 Perovskite Ceramics
Author(s) -
Fu Mao Sen,
Liu Xiao Qiang,
Chen Xiang Ming,
Zeng Yao Wu
Publication year - 2010
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.1551-2916.2009.03459.x
Subject(s) - materials science , microstructure , ceramic , sintering , dielectric , perovskite (structure) , analytical chemistry (journal) , mineralogy , microwave , temperature coefficient , dielectric loss , crystallography , metallurgy , composite material , chemistry , physics , optoelectronics , chromatography , quantum mechanics
Ba[(Zn 1− x Mg x ) 1/3 Nb 2/3 ]O 3 ceramics were synthesized by the solid‐state reaction process, and their microstructure and microwave dielectric properties were investigated. Surface secondary phase Ba 5 Nb 4 O 15 due to the ZnO loss during sintering was detected for all the compositions except for x =1.0. Mg 2+ substitution increased the order–disorder transition temperature and all the Mg 2+ ‐substituted ceramics were well ordered at a rather high sintering temperature. The dielectric constant and τ f decreased approximately in the same linear trend except for x =0.6 and 0.8, while the Q f values for the as‐sintered and annealed ceramics indicated nonlinear variations with compositions inconsistent with the variation of cation‐ordering degree. These results suggested that Q value in the ordered perovskite ceramics was determined not only by the cation‐ordering degree but also by the domain size and its distribution, and the homogeneous domain structure with domain size around 40 nm should be critical for high Q . Good combination of microwave dielectric properties was obtained in the as‐sintered ceramics with x =0.4: ɛ r =36, Q f =94 400 GHz, and τ f =28.6 ppm/°C.