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Lead-free piezoelectric ceramics K0.5Na0.5NbO3xmol%K5.70Li4.07Nb10.23O30 (x = 0–2.5, KNN–xmol%KLN) were prepared by conventional sintering technique. The phase structure and electrical properties of KNN ceramics were investigated as a function of KLN concentration. The results showed that small amount of KLN introduced into the lattice formed a single phase perovskite structure. The KLN modification lowered the phase transition temperature of orthorhombic–tetragonal (TO–T) and increased the Curie temperature (TC). Some abnormal coarse grains were formed in a matrix when the content of KLN was relatively low (1 mol%). However, normally grown grains were only observed when the sintering aid content was increased to 2 mol%. Proper content of KLN decreased the amount of defects, thus the remanent polarization increased and the coercive field decreased markedly, and the sinterability of the KNN ceramics was simultaneously improved with significant increase of piezoelectric properties.


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Microstructure and piezoelectric properties of K5.70Li4.07Nb10.23O30-added K0.5Na0.5NbO3 ceramics

Show Author's information Xuming PANGbJinhao QIUa( )Kongjun ZHUa
Department of Mechanical Engineering, Nanjing Tech University, Nanjing 210009, China
State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Abstract

Lead-free piezoelectric ceramics K0.5Na0.5NbO3xmol%K5.70Li4.07Nb10.23O30 (x = 0–2.5, KNN–xmol%KLN) were prepared by conventional sintering technique. The phase structure and electrical properties of KNN ceramics were investigated as a function of KLN concentration. The results showed that small amount of KLN introduced into the lattice formed a single phase perovskite structure. The KLN modification lowered the phase transition temperature of orthorhombic–tetragonal (TO–T) and increased the Curie temperature (TC). Some abnormal coarse grains were formed in a matrix when the content of KLN was relatively low (1 mol%). However, normally grown grains were only observed when the sintering aid content was increased to 2 mol%. Proper content of KLN decreased the amount of defects, thus the remanent polarization increased and the coercive field decreased markedly, and the sinterability of the KNN ceramics was simultaneously improved with significant increase of piezoelectric properties.

Keywords:

ceramics, sintering aid, phase transformation, electrical properties
Received: 19 January 2014 Revised: 26 March 2014 Accepted: 12 April 2014 Published: 01 June 2014 Issue date: June 2014
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Publication history

Received: 19 January 2014
Revised: 26 March 2014
Accepted: 12 April 2014
Published: 01 June 2014
Issue date: June 2014

Copyright

© The author(s) 2014

Acknowledgements

This work was supported by the Natural Science Foundation of Jiangsu Province, China (BK20130791), Projects of International Cooperation and Exchanges NSFC (51161120326), Aeronautical Science Fund (20131552025), the NUAA Fundamental Research Funds (NS2013008), and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

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