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Microstructure and electrical properties of (1– x )(K 0.5 Na 0.5 )NbO 3 – x BiFeO 3 piezoelectric ceramics
Author(s) -
Li Xiang,
Wu Lang,
Xiao Dingquan,
Zhu Jianguo,
Yu Ping,
Jiang Yihang,
Wu Jiagang
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200824013
Subject(s) - tetragonal crystal system , orthorhombic crystal system , materials science , natural bond orbital , curie temperature , microstructure , crystal structure , sintering , piezoelectricity , ceramic , perovskite (structure) , doping , mineralogy , crystallography , analytical chemistry (journal) , condensed matter physics , metallurgy , composite material , chemistry , ferromagnetism , optoelectronics , density functional theory , physics , computational chemistry , chromatography
Lead–free ceramics (1– x )(K 0.5 Na 0.5 )NbO 3 – x BiFeO 3 doped with 1 mol% Fe 2 O 3 (KNNBF/ x ) have been synthesized by pressureless sintering. With the Fe 2 O 3 doping, the KNNBF/ x ceramics can be well sintered at 1085–1100 °C and exhibit a pure perovskite structure with x < 0.013. It was found that the crystal structure of the KNNBF/ x ceramics changed from orthorhombic to tetragonal and then to pseudocubic phase with the increase of BiFeO 3 content. The composition KNNBF/0.013 near the tetragonal symmetry that separates the orthorhombic and pseudocubic phases exhibits improved electrical properties: d 33 = 173 pC/N, k p = 0.40, ε r = 905, tan δ = 4%, P r = 26 μC/cm 2 , and E c = 11.2 kV/cm, with a high Curie temperature ( T C ) of about 388 °C. Our results suggest that KNNBF/ x are promising lead‐free high temperature piezoelectric ceramics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)