DocumentCode :
1263041
Title :
Characterization of Hard Piezoelectric Lead-Free Ceramics
Author :
Zhang, Shujun ; Lim, Jong Bong ; Lee, Hyeong Jae ; Shrout, Thomas R.
Author_Institution :
Mater. Res. Inst., Pennsylvania State Univ., University Park, PA, USA
Volume :
56
Issue :
8
fYear :
2009
fDate :
8/1/2009 12:00:00 AM
Firstpage :
1523
Lastpage :
1527
Abstract :
K4CuNb8O23 doped K0.45Na0.55NbO3 (KNN-KCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric "hardening" effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of "hard" behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 188degC. The full set of material constants was determined for the KNN-KCN materials. Compared with conventional hard PZT ceramics, the lead-free possessed lower dielectric and piezoelectric properties; however, comparable values of mechanical Q, dielectric loss, and coercive fields were obtained, making acceptor modified KNN based lead-free piezoelectric material promising for high-power applications, where leadfree materials are desirable.
Keywords :
copper compounds; dielectric hysteresis; dielectric losses; dielectric polarisation; electric domain walls; ferroelectric ceramics; ferroelectric coercive field; piezoceramics; piezoelectricity; polymorphic transformations; potassium compounds; sodium compounds; K0.45Na0.55NbO3:K4CuNb8O23; asymmetrical polarization hysteresis loops; coercive fields; dielectric loss; domain wall motion; ferroelectric ceramics; hard piezoelectric lead-free ceramics; internal bias field; mechanical quality factors; piezoelectric hardening; polymorphic phase transition; Ceramics; Dielectric losses; Dielectric materials; Environmentally friendly manufacturing techniques; Ferroelectric materials; Hysteresis; Niobium compounds; Piezoelectric materials; Piezoelectric polarization; Temperature distribution;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/TUFFC.2009.1215
Filename :
5183577
Link To Document :
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