High-Temperature Multilayer Ceramic Capacitors Based on 100-x(94Bi sub(1/2)Na sub(1/2)TiO sub(3)-6BaTiO sub(3))-xK sub(0.5)Na sub(0.5)NbO sub(3)

The potential high-temperature dielectric materials 100-x(94Bi sub(1/2)Na sub(1/2)TiO sub(3)-6BaTiO sub(3))-xK sub(0.5)Na sub(0.5)NbO sub(3) with x = 12, 18, and 24 were processed as bulk samples in order to examine the reduction of sintering temperature by means of CuO as sintering aid. Due to the successful reduction of sintering temperature, low cost Ag:Pd could be used as a co-fired electrode material for multilayer ceramic capacitors (MLCCs). Fabrication of 8 mu m thick, dense MLCCs with self-contained, nonreactive electrodes is reported for a wide range of compositions of Bi sub(1/2)Na sub(1/2)TiO sub(3)-BaTiO sub(3)-K sub(0.5)Na sub(0.5)NbO sub(3). Among the manufactured MLCCs, those with compositions x = 24 showed the most promising dielectric properties for applications where high operating temperatures are needed. The temperature-dependence of permittivity was quite low, revealing a change of less than plus or minus 10% compared to its 150 degree C-value in the range of 40 degree C-225 degree C. For samples sintered at 1000 degree C, an RC constant of about 300 s was obtained at 150 degree C. Furthermore, these x = 24 MLCCs exhibited the finest microstructures among the compositions examined; making it a suitable candidate for further miniaturization of layer thickness as required for state-of-the art devices.