Low temperature sintering of Li2Zn3Ti4O12-xTiO2 microwave dielectric ceramics without glass addition

The sintered densities, crystal structure, surface topography, and microwave dielectric properties of B2O3 and TiO2 dual-doped Li2Zn3Ti4O12 ceramics were investigated. Small amount of B2O3 addition (0.25 wt%) can remarkably improve the densification process of Li2Zn3Ti4O12 ceramics at about 900 degrees C. The sintered Li2Zn3Ti4O12 ceramics with B2O3 added have a cubic spinel structure. With the addition of 0.25 wt% B2O3, Li2Zn3Ti4O12 ceramics exhibit high Qf value of about 62,500 GHz at sintering temperature of 900 degrees C, while a relatively large negative tau(f) value of about - 40.5 ppm/degrees C still limit its application. Based on the addition of 0.25 wt% B2O3, TiO2 was also added in Li2Zn3Ti4O12 ceramics for further improving the tau(f) value. Finally, doped with 0.25 wt% B2O3 and sintered at 900 degrees C, Li2Zn3Ti4O12-1.75TiO(2) ceramics exhibited near zero tau(f) value of 0.5 ppm/degrees C as well as a high Qf value of 55,000 GHz, which is attractive for applications in low temperature co-fired ceramic technologies.