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Effects of Non‐Stoichiometry on the Microstructure, Oxygen Vacancies, and Piezoelectric Properties of CuTa 2 O 6 ‐Doped NKN Ceramics
Author(s) -
Yang SongLing,
Tsai ChengChe,
Liou YiCheng,
Hong ChengShong,
Chu ShengYuan
Publication year - 2013
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.12418
Subject(s) - materials science , sintering , microstructure , stoichiometry , raman spectroscopy , doping , oxygen , ceramic , analytical chemistry (journal) , natural bond orbital , grain size , phase (matter) , mineralogy , chemistry , composite material , physics , optoelectronics , molecule , chromatography , organic chemistry , optics
The effects of non‐stoichiometry on the microstructure, oxygen vacancies, and piezoelectric properties of ( Na 0.5 K 0.5 ) x NbO 3 ( NK x N , where x = 0.98, 1.00, 1.01, and 1.02) ceramics doped with sintering aid CuTa 2 O 6 ( CT ) doping were investigated. X‐ray diffraction (XRD) patterns indicated that a secondary phase formed in CT‐doped NK x N ( NK x NCT ) ceramics with x < 1.00 and that a pure phase was obtained with x ≥ 1.00. The grain size of NK x NCT ceramics increased with increasing x value due to the formation of a liquid phase. The internal bias field, activation energy, and Raman analysis for NK x NCT ceramics showed that the number of induced oxygen vacancies increased with decreasing x value. The high mechanical quality factor ( Q m ) value obtained for NK x NCT ceramics did not correspond to a higher concentration of oxygen vacancies, illustrating that the suitable compensation (excess Na and K ) is more important than the concentration of oxygen vacancies to obtain the ceramics with high Q m values. The NK x NCT ceramics with x = 1.01 exhibited excellent piezoelectric properties, with k p and Q m values of 39.9% and 2,070, respectively.