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Enhancement of Piezoelectric Performance of Lead‐Free NKN ‐Based Ceramics via a High‐Performance Flux— NaF – Nb 2 O 5
Author(s) -
Liu Cheng,
Liu Peng,
Kobayashi Keisuke,
Qu Weiguo,
Randall Clive A.
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.12461
Subject(s) - materials science , sintering , dielectric , natural bond orbital , ceramic , doping , mineralogy , piezoelectricity , flux (metallurgy) , analytical chemistry (journal) , chemistry , composite material , metallurgy , optoelectronics , chromatography , density functional theory , computational chemistry
x ( NaF −0.5 Nb 2 O 5 )−(1 − x )[( Na 0.5 K 0.5 )( Nb 0.8 Ta 0.2 ) O 3 ] (100 x NN − NKNT ) piezoelectric ceramics were fabricated to high densities above 97% when sintering at temperatures ~1200°C. Compared with pure ( Na , K ) NbO 3 ( NKN ), dielectric constants of the NaF – Nb 2 O 5 flux‐doped NKNT ceramics were increased whereas dielectric losses remained low. High field polarization switching showed very square hysteresis loops, but the coercive fields were decreased through a “softening” doping effect induced by the flux. A R ayleigh analysis inferred that the extrinsic contribution from the domain wall dynamics was increased with the flux addition. Collectively, all the experimental observations suggested that NaF – Nb 2 O 5 was, in part, soluble in the structure and highly suitable for obtaining a stable NKN system with improved piezoelectric performance.