Microstructure and microwave dielectric properties of (1-x)Ba(Co1/3Nb2/3)O-3-xBa(Zn1/3Nb2/3)O-3 ceramics

Abstract

The microstructure and microwave dielectric properties of (1 - x)Ba(Co1/3Nb2/3)O-3-xBa(Zn1/3Nb2/3)O-3 [(1 - x)BCN-xBZN] ceramics with 0.0 less than or equal to x less than or equal to 1.0 were investigated. When the sintering temperature was 1400degreesC, a homogeneous phase with a I : 2 ordered structure was found in the specimens with x less than or equal to 0.3 but for the specimens with x greater than or equal to 0.6, a disordered structure and BaNb6O16 second phase were found. The grain growth related to the BaNb6O16 second phase occurred in the specimens with x greater than or equal to 0.5. The temperature coefficient of the resonant frequency (tau(f)) increased with increasing x, and the specimens with 0.3 less than or equal to x less than or equal to 0.4 have zero tau(f). Dielectric constant (epsilon(f)) increased with the increase in x and was about 34.5 when x = 0.3. For the specimens with x less than or equal to 0.3, the Q x f value was high but decreased as x exceeded 0.3. The maximum Q x f value, 97,000 GHz, was obtained for 0.7BCN-0.3BZN ceramics sintered at 1400degreesC for 20h.