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Magneto‐Dielectric Properties of Mg–Cu–Co Ferrite Ceramics: I. Densification Behavior and Microstructure Development
Author(s) -
Kong L. B.,
Li Z. W.,
Lin G. Q.,
Gan Y. B.
Publication year - 2007
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.1551-2916.2007.01869.x
Subject(s) - materials science , microstructure , grain growth , sintering , ferrite (magnet) , ceramic , dielectric , grain size , metallurgy , composite material , optoelectronics
The densification, grain growth, and microstructure development of Mg–Cu–Co ferrite ceramics (MgFe 1.98 O 4 , Mg 1− x Cu x Fe 1.98 O 4 , with x =0.10–0.30 and Mg 0.90− x Co x Cu 0.10 Fe 1.98 O 4 , with x =0.05–0.20) were studied. The primary objective was to develop magneto‐dielectric materials for miniaturization of high frequency and very‐high frequency antennas. It was found that magnesium ferrite (MgFe 1.98 O 4 ) is a promising magneto‐dielectric material. However, due to its poor densification, it could not be fully sintered at a temperature below 1200°C. High‐temperature sintering resulted in undesirable electrical and dielectric properties, due to the formation of Fe 2+ ions. The poor densification and slow grain growth rate of MgFe 1.98 O 4 can be considerably improved by incorporating Cu, due to the occurrence of liquid‐phase sintering at a high temperature. A critical concentration of Cu was observed for Mg 1− x Cu x Fe 1.98 O 4 , above which both densification and grain growth were maximized or saturated. The presence of Co did not have a significant influence on the densification and grain growth of the Mg‐based ferrite ceramics.