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Ferroelectric and Piezoelectric Properties of Fine‐Grained Na 0.5 K 0.5 NbO 3 Lead‐Free Piezoelectric Ceramics Prepared by Spark Plasma Sintering
Author(s) -
Li JingFeng,
Wang Ke,
Zhang BoPing,
Zhang LiMin
Publication year - 2006
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.1551-2916.2005.00743.x
Subject(s) - natural bond orbital , materials science , spark plasma sintering , piezoelectricity , curie temperature , ceramic , orthorhombic crystal system , ferroelectricity , sintering , mineralogy , ferroelectric ceramics , annealing (glass) , analytical chemistry (journal) , dielectric , composite material , crystal structure , crystallography , condensed matter physics , density functional theory , optoelectronics , chemistry , ferromagnetism , computational chemistry , physics , chromatography
Lead‐free piezoelectric ceramics have received attention because of increasing interest in environmental protection. Niobate ceramics such as NaNbO 3 and KNbO 3 have been studied as promising Pb‐free piezoelectric ceramics, but their sintering densification is fairly difficult. In the present study, highly dense Na 0.5 K 0.5 NbO 3 ceramics were prepared using spark plasma sintering (SPS). Although the SPS temperature was as low as 920°C, the density of the Na 0.5 K 0.5 NbO 3 solid solution ceramics was raised to 4.47 g/cm 3 (>99% of the theoretical density). After post‐annealing in air, reasonably good ferroelectric and piezoelectric properties were obtained in the Na 0.5 K 0.5 NbO 3 ceramics with submicron grains. The crystal phase of the Na 0.5 K 0.5 NbO 3 has an orthorhombic structure. The Curie temperature is 395°C and the piezoelectric parameter ( d 33 ) of the Na 0.5 K 0.5 NbO 3 ceramics reached 148 pC/N.