STRUCTURAL TRANSITION AND MICROWAVE DIELECTRIC PROPERTIES OF ZnNb2O6-TiO2 SINTERED AT LOW TEMPERATURES

The addition of CuO to ZnNb2O6-TiO2 lowered the sintering temperature to approx 900 C in comparison to approx 1200 C for samples without CuO. The effect of CuO additions on the phase transitions and microwave dielectric properties of 0.42ZnNb2O6-0.58TiO2 has been investigated using powder XRD and a network analyzer. The structural transition from columbite and rutile to ixiolite was influenced by both the sintering temperature as well as the amount of CuO. These influences, however, were competing. It is assumed that the different constitutions of crystal structure of ZnNb2O6-TiO2 samples due to increase in either the sintering temperature or the amount of CuO lead to variation in the microwave dielectric properties. The tf was modified to approx 0 ppm/C, as a result of the variation in phase constitutions as a function of composition. 21 refs.