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Grain Growth Control and Dopant Distribution in ZnO‐Doped BaTiO 3
Author(s) -
Caballero Amador C.,
Fernández José F.,
Moure Carlos,
Durán Pedro,
Chiang YetMing
Publication year - 1998
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.1151-2916.1998.tb02430.x
Subject(s) - dopant , materials science , grain growth , sintering , grain boundary , doping , microstructure , chemical engineering , mineralogy , metallurgy , chemistry , optoelectronics , engineering
ZnO additions to BaTiO 3 have been studied in order to determine the role of this dopant on sintering and microstructure development. As a consequence of a better initial dopant distribution, samples doped with 0.1 wt% zinc stearate show homogeneous fine‐grained microstructure, while a doping level of 0.5 wt% solid ZnO is necessary to reach the same effect. When solid ZnO is used as the dopant precursor, ZnO is redistributed among the BaTiO 3 particles during heating. Since no liquid formation has been detected for temperatures below 1400°C in the system BaTiO 3 ‐ZnO, it is proposed that dopant redistribution takes place by vapor‐phase transport and grain boundary diffusion. Shrinkage and porosimetry measurements have shown that grain growth is inhibited during the first step of sintering for the doped samples. STEM‐EDX analysis revealed that solid solubility of ZnO into the BaTiO 3 lattice is very low, being strongly segregated at the grain boundaries. Grain growth control is attributed to a decrease in grain boundary mobility due to solute drag. Because of its effectiveness in controlling grain growth, ZnO appears to be an attractive additive for BaTiO 3 dielectrics.