1. Processing and Piezoelectric Properties of Lead-Free (K,Na) (Nb,Ta) O3 Ceramics
- Author
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Toshinobu Yogo, Wataru Sakamoto, Toshiaki Yamaguchi, Koichi Kikuta, Masato Matsubara, and Shin-ichi Hirano
- Subjects
Materials science ,Doping ,Analytical chemistry ,Mineralogy ,Piezoelectricity ,Phase (matter) ,visual_art ,Materials Chemistry ,Ceramics and Composites ,Melting point ,visual_art.visual_art_medium ,Ceramic ,Solid solution ,Natural bond orbital ,Perovskite (structure) - Abstract
The preparations of (K 0.5 Na 0.5 )NbO 3 (KNN)-based ceramics were studied as lead-free piezoelectric materials. The authors found that the addition of CuO greatly enhanced the sinterability of the KNN-based ceramics. The sinterability and piezoelectric properties of these ceramics were dependent upon the A/B ratio, CuO doping, and the formation of a solid solution with KTaO 3 . Perovskite (K 0.5 Na 0.5 ) x NbO 3 (x = A/B ratio) was synthesized with A/B ratios of 1.00 and 1.05 by CuO doping, while (K 0.5 Na 0.5 )NbO 3 contained K 4 CuNb 8 O 23 as a second phase with A/B ratios below 0.98. Although the A site-rich (K 0.5 Na 0.5 )NbO 3 (x = 1.00 and 1.05) ceramics exhibited deliquescence, the A site-poor (K 0.5 Na 0.5 )NbO 3 (x ≤ 0.98) ceramics with K 4 CuNb 8 O 23 had higher densities without deliquescence. K 4 CuNb 8 O 23 also improved Q m , which reached 1400 for the (K 0.5 Na 0.5 ) 1.0 NbO 3 doped with 0.5 mol% K 4 CuNb 8 O 23 . The formation of a solid solution with KTaO 3 raised the melting point of the system and also improved its sinterability. The k p and Q m of (K 0.5 Na 0.5 ) 0.97 (Nb 0.95 Ta 0.05 )O 3 with CuO were 0.41 and 1400, respectively.
- Published
- 2005