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Investigation of CuO ‐Doped NKN Ceramics with High Mechanical Quality Factor Synthesized by a B ‐Site Oxide Precursor Method
Author(s) -
Yang SongLing,
Tsai ChengChe,
Liou YiCheng,
Hong ChengShong,
Li BingJing,
Chu ShengYuan
Publication year - 2012
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.1551-2916.2011.04903.x
Subject(s) - activation energy , microstructure , analytical chemistry (journal) , ceramic , materials science , dielectric , doping , mineralogy , dopant , chemistry , metallurgy , chromatography , optoelectronics
In this study, composition of ( Na 0.5 K 0.5 )NbO 3 + x mol% CuO ceramics ( NKNC x , where x = 0–1 mol%) were separately prepared using the B ‐site oxide precursor method ( BO method) and the conventional mixed oxide method ( MO method). The diffracted angles of the NKNC x ceramics decreased as the concentrations of CuO dopants increased, because Nb 5+ ions were replaced by Cu 2+ ions, leading to the formation of oxygen vacancies. The microstructures of NKNC x ceramics prepared using the BO method were more homogeneous microstructures than that of ceramics prepared using the MO method. The mechanical quality factor ( Q m ) and dielectric constant (ε 33 T /ε 0 ) of NKNC x ceramics prepared using the BO method were therefore by 21% and 25% better, respectively. The activation energy and internal bias field were measured and calculated to confirm the presence of oxygen vacancies. A low activation energy corresponds to a high Q m value. NKN ceramics with 0.75 mol% CuO doping prepared using the BO method had an activation energy and internal bias field of 0.95 eV and 3.5 kV/cm, respectively, at x = 0.75 mol%. The bulk density, k p , Q m , ε 33 T /ε 0 , and dielectric loss of NKNC x ceramics with this composition were 4.488 g/cm 3 , 41.5%, 2100, 280, and 0.15%, respectively.