Zhu, FY, Ward, MB, Li, JF et al. (1 more author) (2015) Core-shell Grain Structures and Dielectric Properties of Na0.5K0.5NbO3-LiTaO3-BiScO3 Piezoelectric Ceramics. Acta Materialia, 90. 204 - 212. ISSN 1359-6454
Abstract
The origins of distinctive compositional dependence of relative permittivity, ɛr, in the Pb-free piezoelectric system (1-x)Na0.5K0.5NbO3-xLiTaO3, x≤ 10 mol.% modified with BiScO3 have been revealed using transmission electron microscopy with energy dispersive X-ray analysis (TEM-EDX). As the LiTaO3 content increased the Curie peak at ~370°C in ɛr –T plots became more diffuse, and at x= 5 mol.% an additional higher temperature peak occurred. TEM-EDX analysis showed the change in dielectric properties at x= 5 mol.% was due to a change in microstructure: micron-scale grains were replaced by submicron grains exhibiting core-shell chemical segregation. The outer shell was similar to the target solid solution composition, slightly enriched in Bi, Sc and Ta, whilst the core approximated to (Na, K, Li)NbO3 and was responsible for the additional dielectric peak. Examples of a novel three-tier metastable grain structure were observed for certain compositions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2015, Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Acta Materialia. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | core shell structure; lead-free; NKN-based; dielectric; TEM |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Materials Research (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 26 Aug 2015 13:43 |
Last Modified: | 06 Nov 2017 07:53 |
Published Version: | http://dx.doi.org/10.1016/j.actamat.2015.02.034 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.actamat.2015.02.034 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:84653 |
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