Thermal decomposition and kinetic analysis of relaxor ferroelectric lead magnesium niobate
Resource
Journal of the European Ceramic Society 18 (11): 1599-1607
Journal
Journal of the European Ceramic Society
Journal Volume
18
Journal Issue
11
Pages
1599-1607
Date Issued
1998
Date
1998
Author(s)
Abstract
The reaction mechanisms and kinetics of thermal decomposition of the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 powder at elevated-temperatures have been investigated. The decomposition of Pb(Mg1/3Nb2/3)O3 is characterized by an initial formation of pyrochlore phase, associated with evaporation of PbO. Then pyrochlore phase subsequently gets dissociated, resulting in the formation of Mg4Nb2O9 and MgNb2O6. The decomposition amounts of Pb(Mg1/3Nb2/3)O3 as well as pyrochlore phase increase monotonously with increase in the reaction temperature and time. Based on the isothermal analysis of reaction kinetics, the rate-controlling step for decomposition of Pb(Mg1/3Nb2/3)O3 is determined to be the chemical reaction of Pb(Mg1/3Nb2/3)O3 itself with activation energy of 234kJmol-1. On the other hand, during the decomposition of pyrochlore phase, a molten microstructure is formed, and reaction kinetics changes greatly. This decomposition of pyrochlore phase is confirmed to be a first-order reaction with higher activation energy of 407kJmol-1. © 1998 Elsevier Science Limited. All rights reserved.
Type
journal article
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