Open AccessEffects of K4CuNb8O23 and GeO2 addition on microstructure and piezoelectric properties in KNbO3 ceramics
Author(s) -
Hiroki Kato,
Mirai Ishida,
Yumi Akiyama
Publication year - 2019
Publication title -
japanese journal of applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 129
eISSN - 1347-4065
pISSN - 0021-4922
DOI - 10.7567/1347-4065/ab3627
Subject(s) - microstructure , sintering , piezoelectricity , doping , decomposition , ceramic , materials science , phase (matter) , mineralogy , analytical chemistry (journal) , crystallography , chemistry , metallurgy , composite material , optoelectronics , organic chemistry
A combined additives study of lead-free KNbO 3 (KN) ceramics in the solid-state reaction was performed to improve the mechanical quality factor ( Q m ) for high power piezoelectric applications. Improved Q m values of 1137 and 1241 were confirmed in KN specimens with addition of 1.0 mol% K 4 CuNb 8 O 23 (KCN) and 1.0 mol% KCN + 0.5 wt% GeO 2 , respectively. It is important for achievement of the higher Q m in KN systems to control the composition of the Cu segregated phase. In this study, the Cu segregated phase which was necessary to improve the Q m resulted from decomposition of the KCN compound during the sintering. Co-doping of KCN and GeO 2 to KN specimens has a remarkable effect in suppressing the deliquescence accompanying KCN addition and improvement of the Q m without significant deterioration of the electromechanical coupling factor k 31 .
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