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(K,Na)NbO 3 ‐Based Ceramics for Piezoelectric “Hard”Lead‐Free Materials
Author(s) -
Lim Jong Bong,
Zhang Shujun,
Jeon JaeHo,
Shrout Thomas R.
Publication year - 2010
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.1551-2916.2009.03528.x
Subject(s) - piezoelectricity , natural bond orbital , orthorhombic crystal system , ceramic , materials science , perovskite (structure) , coercivity , dipole , mineralogy , analytical chemistry (journal) , crystallography , chemistry , condensed matter physics , crystal structure , composite material , density functional theory , physics , computational chemistry , organic chemistry , chromatography
Lead‐free piezoelectric ceramics (K 0.45 Na 0.55 )NbO 3 (KNN) modified by K 4 CuNb 8 O 23 (KCN) were synthesized using conventional ceramic processing. All the ceramics possessed the perovskite structure with orthorhombic symmetry. Results revealed that the addition of KCN was effective in enhancing the density of KNN. The addition of KCN was found to slightly decrease T o – t and T c . The coercive field ( E c ) was found to maintain the same value by the addition of KCN while the internal bias ( E i ) sharply increased to 4 kV/cm with 0.5 mol% KCN. The low migration rate of defect dipoles was correlated with the build‐up of E i , which was responsible for the stabilization of the domain wall and the improvement of Q m . Therefore, KNN–KCN0.5 exhibited excellent piezoelectric properties of d 33 (100 pC/N), k p (33%), and Q m (1500), making them promising candidates for applications requiring hard piezoelectrics.