PHASE-STRUCTURE AND DIELECTRIC-PROPERTIES OF BI2O3-ZNO-NB2O5-BASED DIELECTRIC CERAMICS

Phase structures and dielectric properties of the compounds with formu las BixZn2/3Nb4/3O4+3x/2 (group M), BixZn8/3-x-Nb4/3O6+x/2 (group V), and BixZn2-2x/3Nb2-2x/3O7 (group W) have been investigated. Initial re sults indicate that a cubic pyrochlore structure is the predominant ph ase of these compounds. Most of the measured ceramic specimens exhibit dielectric properties suitable as temperature-stable and temperature- compensating dielectrics in the capacitor industry. The values of the dielectric constant K are 80-160, while those of the temperature coeff icient are -500 to +60 ppm/degrees-C. The composition limits of the si ngle pyrochlore phase are determined mainly by Bi2O3 additives.