Effect of Bi₂O₃ Addition on the Microstructure and Electrical Properties of Lead-Free (Na_0.5K_0.5)NbO₃-Ba(Sn_0.02Ti_0.98)O₃ Ceramics

Abstract:

PbZrO3-PbTiO3 (PZT)-based ceramics are playing a dominant role in piezoelectric materials, their evaporation of harmful lead oxide during the sintering process causes a crucial environment problem. It is necessary to search for lead-free piezoelectric materials that have such excellent properties as those found in the PZT-based ceramics. Therefore (Na0.5K0.5)NbO3-based solid solutions were studied to improve piezoelectric properties. In the present study, various quantities of Bi2O3 were added into 0.98(Na0.5K0.5)NbO3-0.02Ba(Sn0.02Ti0.98)O3 (0.98NKN-0.02BST) ceramics. It was found that 0.98NKN-0.02BST with the addition of 0~4.0 wt.% Bi2O3 exhibit relatively good piezoelectric properties. For 0.98NKN-0.02BST ceramic with the addition of 1.0 wt.% Bi2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.21 and 0.46, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 2.2. It is obvious that 0.98NKN-0.02BST solid solution ceramic by adding low quantities of Bi2O3 is one of the promising lead-free ceramics for high frequency electromechanical transducer applications.

• Periodical: Applied Mechanics and Materials (Volumes 284-287)
• Pages: 3-7
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.284-287.3
• Online since: January 2013
• Authors: Chun Huy Wang
• Keywords: Crystal Structure, Dielectric Property, Lead-Free Piezoceramic, Piezoelectric Properties, Poling, Sintering

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