Low-Temperature Sintering of K0.5Na0.5NbO3 Ceramics
The objective of this work was to lower the sintering temperature of K0.5Na0.5NbO3 (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 (/0) and losses (tan), measured at 10 kHz, the piezo d33 coefficient, the electromechanical coupling and mechanical quality factors (kp, kt, Qm) 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.
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Document Type: Research Article
Affiliations: Department of Electronic Ceramics, Jožef Stefan Institute, Ljubljana 1000, Slovenia
Publication date: 2008-07-01