CaZrO3, a Ni-co-sinterable dielectric material for base metal-multilayer ceramic capacitor applications

The aim of this work is to obtain CaZrO3 powders that are co-sinterable with nickel electrodes. Since CaZrO3 is often sintered at temperatures higher than 1550 degreesC to achieve high sample densities, obtaining a powder co-sinterable with Ni would require lower sintering temperatures. The co-sintering also requires that the reaction takes place in a reducing atmosphere. After optimizing the thermal cycle for the phase synthesis, several approaches were investigated to decrease the CaZrO3 sintering temperature. First, the grain size effect on the densification was studied to enhance the calcined powder's reactivity before sintering. In addition, the Ca/Zr ratio was investigated, and the effect of doping with lithium salts was examined. Similarly, in order to allow co-sintering with base-metal inner electrodes, the sinterability and the properties of the dielectric were examined in a reducing atmosphere. Finally, a co-sintered material was synthesized, resulting in good dielectric properties. The samples were analyzed in terms of structure and microstructure. The electric and dielectric properties were also measured on sintered samples. (C) 2003 Elsevier Ltd. All rights reserved.