Effect of H3BO3 addition on the sintering behavior and microwave dielectric properties of wolframite-type MgZrNb2O8 ceramics

The effect of H3BO3 addition on sintering behavior, microstructure and microwave dielectric properties of MgZrNb2O8 ceramics was investigated by solid-state method. With H3BO3 addition, the densification of MgZrNb2O8 ceramics was improved significantly, and the tau(f) was adjusted to shift toward zero direction. Due to the effect of liquid phase produced from H3BO3 addition, the sintering temperature was lowered effectively. The variations in the dielectric constant (epsilon(r)) and the Q.f values of the MgZrNb2O8 ceramics are depended on the amount of H3BO3 doping and the sintering temperature. As a result, an optimal microwave dielectric property of Q.f = 58,930 GHz, epsilon(r) = 23.72, and tau(f) = -13.19 ppm/degrees C was obtained for the MgZrNb2O8 ceramic with 1 wt% H3BO3 addition sintered at 1200 degrees C for 4 h. The relatively low sintering temperature and high dielectric properties in microwave range would make MgZrNb2O8 ceramics promising for application in electronics. (C) 2015 Elsevier B.V. All rights reserved.