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Low‐Temperature Sintering of K 0.5 Na 0.5 NbO 3 Ceramics
Author(s) -
Bernard Janez,
Benčan Andreja,
Rojac Tadej,
Holc Janez,
Malič Barbara,
Kosec Marija
Publication year - 2008
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.1551-2916.2008.02447.x
Subject(s) - sintering , materials science , ceramic , germanate , natural bond orbital , analytical chemistry (journal) , permittivity , relative density , mineralogy , dielectric , piezoelectricity , relative permittivity , composite material , doping , chemistry , optoelectronics , density functional theory , computational chemistry , chromatography
The objective of this work was to lower the sintering temperature of K 0.5 Na 0.5 NbO 3 (KNN) without reducing its piezoelectric properties. The KNN was sintered using 0.5, 1, 2, and 4 mass% of (K, Na)‐germanate. The influence of the novel sintering aid, based on alkaline germanate with a melting point near 700°C, on the sintering, density, and piezoelectric properties of KNN is presented. The alkaline‐germanate‐modified KNN ceramics reach up to 96% of theoretical density at sintering temperatures as low as 1000°C, which is approximately 100°C less than the sintering temperature of pure KNN. The relative dielectric permittivity (ɛ/ɛ 0 ) and losses (tanδ), measured at 10 kHz, the piezo d 33 coefficient, the electromechanical coupling and mechanical quality factors ( k p , k t , Q m ) of KNN modified with 1 mass% of alkaline germanate are 397, 0.02, 120 pC/N, 0.40, 0.44, and 77, respectively. These values are comparable to the best values obtained for KNN ceramics sintered above 1100°C.