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Enhancing Electrical Properties in NBT–KBT Lead‐Free Piezoelectric Ceramics by Optimizing Sintering Temperature
Author(s) -
Zhang YaRu,
Li JingFeng,
Zhang BoPing
Publication year - 2008
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.1551-2916.2008.02469.x
Subject(s) - sintering , materials science , phase boundary , piezoelectricity , tetragonal crystal system , ceramic , phase (matter) , composite material , mineralogy , chemistry , organic chemistry
Conventional sintering of (Na 1− x K x ) 0.5 Bi 0.5 TiO 3 (abbreviated as NKBT x , x =18–22 mol%) lead‐free piezoelectric ceramics was investigated to clarify the optimal sintering temperature for densification and electrical properties. Both sintered density and electrical properties were sensitive to sintering temperature; particularly, the piezoelectric properties deteriorated when the ceramics were sintered above the optimum temperature. The NKBT20 and NKBT22 ceramics synthesized at 1110°–1170°C showed a phase transition from tetragonal to rhombohedral symmetry, which was similar to the morphotropic phase boundary (MPB). Because of such MPB‐like behavior, the highest piezoelectric constant ( d 33 ) of about 192 pC/N with a high electromechanical coupling factor ( k p ) of about 32% were obtained in the NKBT22 ceramics sintered at 1150°C.