Effect of Li2O–V2O5 on the low temperature sintering and microwave dielectric properties of Li1.0Nb0.6Ti0.5O3 ceramics

Li2O–Nb2O5–TiO2 based ceramic systems have been the candidate materials for LTCC application, due to their high dielectric constant and Q × f value and controllable temperature coefficient in the microwave region. However, the sintering temperature was relatively higher (above 1100 °C) for practical application. In this study, dielectric properties of Li(1+x−y)Nb(1−x−3y)Ti(x+4y)O3 solid solution were studied with different x and y contents and among them, the Li1.0Nb0.6Ti0.5O3 composition (x = 0.1, y = 0.1) was selected, due to its reasonable dielectric properties to determine the possibility of low temperature sintering. The effects of 0.17Li2O–0.83V2O5, as a sintering agent, on sinterability and microwave dielectric properties of Li1.0Nb0.6Ti0.5O3 ceramics were investigated as a function of the sintering agent content and sintering temperature. With addition of 0.17Li2O–0.83V2O5 above 0.5 wt%, the specimens were well densified at a relatively lower temperature of 850 °C. Only slight decrease in apparent density was observed with increasing 0.17Li2O–0.83V2O5 content above 0.75 wt%. In the case of 0.5 wt% 0.17Li2O–0.83V2O5 addition, the values of dielectric constant and Q × f reached maximum. Further addition caused inferior microstructure, resulting in degraded dielectric properties. For the specimens with 0.5 wt% 0.17Li2O–0.83V2O5 sintered at 850 °C, dielectric constant, Q × f and TCF values were 64.7, 5933 GHz and 9.4 ppm per °C, respectively.