PREPARATION AND DIELECTRIC PROPERTIES OF Bi1.5Zn1.0Nb1.5O7 AND Bi1.5Zn0.92Nb1.5O6.92 PYROCHLORE CERAMICS

Bi1.5Zn1.0Nb1.5O7 and Bi1.5Zn0.92Nb1.5O6.92 pyrochlore compositions were prepared and investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and their dielectric properties were measured. XRD of Bi1.5Zn0.92Nb1.5O6.92 gave only single phase pyrochlore but second phases were observed in the XRD of Bi1.5Zn1.0Nb1.5O7. SEM supported X-ray results but in the microstructure of Bi1.5Zn1.0Nb1.5O7 composition a Zn-rich phase was also observed in additon to pyrochlore and ZnO. Bi1.5Zn0.92Nb1.5O6.92 pyrochlore had higher dielectric constant and lower loss values than Bi1.5Zn1.0Nb1.5O7 composition between 25-200 degrees C in the frequency range of 10 kHz-2 MHz, possibly due to presence of second phases in Bi1.5Zn1.0Nb1.5O7.