Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1476470 | Journal of the European Ceramic Society | 2007 | 4 Pages |
Abstract
The Ba5Nb4O15 ceramic offers attractive dielectric properties (Ér â¼Â 39, tan(δ) < 10â3, Ïi â¼Â 1012 Ω cm) but exhibits a high permittivity temperature coefficient (ÏÉ â¼Â â171 ppm °Câ1). In order to tune this parameter, substitutions on the Ba and Nb sites by, respectively, Mg, Ca, Sr and V, Ta, Sn have been investigated. Two interesting formulations have been identified, Ba2.5Mg2.5Nb4O15 and Ba5Nb3SnO14.5 as nominal compositions, with temperature coefficients of â44 and â30 ppm °Câ1, respectively. More attention has been paid to the Ba5Nb3SnO14.5 compound (named 504Sn25) in which BaSnO3 has been clearly identified as a secondary phase. BaSnO3, having a positive and very high temperature coefficient (+393 ppm °Câ1), seems to be responsible for the ÏÉ lowering of 504Sn25. Furthermore B2O3 addition as sintering aid has been successfully investigated for increasing the Ba5Nb3SnO14.5 sample density. In terms of dielectric properties, it induces an increase of the permittivity and of the insulating resistivity, while the control of ÏÉ is maintained. Finally, the formulation 504Sn25 + 15 mol% B2O3 sintered at 1200 °C has a value of 17.8 as dielectric constant and â1 ppm °Câ1 as ÏÉ value, that evidences the potentiality of this material to be used as temperature stable capacitor.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Sophie d'Astorg, Sylvain Marinel, Ahcène Chaouchi, Gregory Goupil,