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Investigation of grain boundary diffusion and grain growth of lithium zinc ferrites with low activation energy
Author(s) -
Xu Fang,
Zhang Huaiwu,
Xie Fei,
Liao Yulong,
Li Yuanxun,
Li Jie,
Jin Lichuan,
Yang Yan,
Gan Gongwen,
Wang Gang,
Zhao Qiang
Publication year - 2018
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/jace.15739
Subject(s) - sintering , grain growth , materials science , activation energy , ceramic , grain boundary diffusion coefficient , ferrite (magnet) , grain boundary , grain size , spinel , ionic radius , analytical chemistry (journal) , chemical engineering , metallurgy , mineralogy , composite material , ion , microstructure , chemistry , chromatography , engineering , organic chemistry
Activation energy and diffusion kinetics are important factors for grain growth and densification. Here, Bi 2 O 3 was introduced into Li 0.43 Zn 0.27 Ti 0.13 Fe 2.17 O 4 ferrite ceramics via a presintered process to lower the reaction activation energy and to achieve low temperature sintering. Interestingly, Bi 3+ ions entered the lattice and substituted for Fe 3+ in the B‐site (i.e., a pure LiZn spinel ferrite). Also, SEM image results show that Bi 2 O 3 ‐substituted LiZn ferrite ceramics have low critical temperature for grain growth (920°C), which is very advantageous for LTCC technology. This indicates that Bi 2 O 3 is an excellent dopant for ceramics. Furthermore, to promote normal grain growth of the ceramics at low temperatures, different volumes of V 2 O 5 additive were added at the final sintering stage. Results indicate that an optimal volume of V 2 O 5 additive promotes grain growth (with no abnormal grains) and enhances magnetic performances of the ceramics at low sintering temperature. Finally, adding the optimal volume of V 2 O 5 additive resulted in a homogeneous and compact LiZnTiBi ferrite ceramic with larger grains (average size of ~8 μm), high 4π M s (~4100 gauss), and low ΔH (~190 Oe) obtained (at 900°C). Moreover, the doping method reported in this study also provides a reference for other low temperature sintered ceramics.