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Orthorhombic‐pseudocubic phase transition and piezoelectric properties of (Na 0.5 K 0.5 )(Nb 1− x Sb x )‐SrZrO 3 ceramics
Author(s) -
Lee KuTak,
Kim DaeHyeon,
Park JongSeong,
Lee TaeGon,
Cho SungHoon,
Park SuJin,
Kang JongYoon,
Nahm Sahn
Publication year - 2017
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/jace.14985
Subject(s) - orthorhombic crystal system , tetragonal crystal system , materials science , phase boundary , crystallography , phase transition , phase (matter) , piezoelectricity , curie temperature , analytical chemistry (journal) , crystal structure , condensed matter physics , chemistry , composite material , physics , organic chemistry , chromatography , ferromagnetism
0.96(Na 0.5 K 0.5 )(Nb 1− x Sb x )‐0.04SrZrO 3 ceramics with 0.0≤ x ≤0.06 were well sintered at 1060°C for 6 hours without a secondary phase. Orthorhombic‐tetragonal transition temperature ( T O ‐T ) and Curie temperature ( T C ) decreased with the addition of Sb 2 O 5 . The decrease in T C was considerable compared to that in T O ‐T , and thus the tetragonal phase zone disappeared when x exceeded 0.03. Therefore, a broad peak for orthorhombic‐pseudocubic transition as opposed to that for orthorhombic‐tetragonal transition appeared at 115°C‐78.2°C for specimens with 0.04≤ x ≤0.06. An orthorhombic structure was observed for specimens with x ≤0.03. However, the polymorphic phase boundary structure containing orthorhombic and pseudocubic structures was formed for the specimens 0.04≤ x ≤0.06. Furthermore, a specimen with x =0.055 exhibited a large piezoelectric strain constant of 325 pC /N, indicating that the coexistence of orthorhombic and pseudocubic structures could improve the piezoelectric properties of (Na 0.5 K 0.5 )NbO 3 ‐based lead‐free piezoelectric ceramics.