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Microstructure, Piezoelectric, and Ferroelectric Properties of Bi 2 O 3 ‐Added (K 0.5 Na 0.5 )NbO 3 Lead‐Free Ceramics
Author(s) -
Du Hongliang,
Liu Daijun,
Tang Fusheng,
Zhu Dongmei,
Zhou Wancheng,
Qu Shaobo
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.01846.x
Subject(s) - natural bond orbital , materials science , sintering , tetragonal crystal system , orthorhombic crystal system , analytical chemistry (journal) , mineralogy , microstructure , ferroelectricity , piezoelectricity , perovskite (structure) , ceramic , melting point , dielectric , crystallography , crystal structure , metallurgy , chemistry , composite material , density functional theory , optoelectronics , chromatography , computational chemistry
Lead‐free piezoelectric (K 0.5 Na 0.5 )NbO 3 – x wt% Bi 2 O 3 ceramics have been synthesized by an ordinary sintering technique. The addition of Bi 2 O 3 increases the melting point of the system and improves the sintering temperature of (K 0.5 Na 0.5 )NbO 3 ceramics. All samples show a pure perovskite phase with a typical orthorhombic symmetry when the Bi 2 O 3 content <0.7 wt%. The phase transition temperature of orthorhombic–tetragonal ( T O − T ) and tetragonal–cubic ( T C ) slightly decreased when a small amount of Bi 2 O 3 was added. The remnant polarization P r increased and the coercive field E c decreased with increasing addition of Bi 2 O 3 . The piezoelectric properties of (K 0.5 Na 0.5 )NbO 3 ceramics increased when a small amount of Bi 2 O 3 was added. The optimum piezoelectric properties are d 33 =140 pC/N, k p =0.46, Q m =167, and T C =410°C for (K 0.5 Na 0.5 )NbO 3 –0.5 wt% Bi 2 O 3 ceramics.