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Oxygen transport during formation and decomposition of AgNbO3 and AgTaO3

Published online by Cambridge University Press:  31 January 2011

Matjaz Valant ,
Anna-Karin Axelsson ,
Bin Zou  and
Neil Alford
Matjaz Valant*
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Anna-Karin Axelsson
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Bin Zou
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Neil Alford
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
*
a)Address all correspondence to this author. e-mail: m.valant@imperial.ac.uk
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Abstract

A thermogravimetric method was used to analyze intermediate processes involved in the formation and decomposition of AgNbO3and AgTaO3perovskites. Critical parameters that control the kinetics of the formation are associated with oxygen transport. The Nb2O5crystal structure has a capacity to trap molecular oxygen, which evolves during the decomposition of Ag2O that is present in a starting mixture. The formation of the perovskite phase involves a simultaneous reaction of three species: O2, Ag, and Nb2O5/Ta2O5. As the trapped molecular oxygen is in the immediate vicinity of the reaction site, the kinetics of the reaction is significantly accelerated. An absence of the molecular oxygen in the solid-state phase cannot be compensated for with an increase in a partial pressure of oxygen in the gas phase, that is, application of oxygen atmosphere.

Keywords

NbPiezoelectricTa
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 6 , June 2007 , pp. 1650 - 1655
Copyright
Copyright © Materials Research Society2007

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