Co2O3 substitution effects on the structure and microwave dielectric properties of low-firing (Zn0.9Mg0.1)TiO3 ceramics

Low-firing (Zn0.9Mg0.1)1−xCoxTiO3 (x = 0.02-0.10) (ZMCxT) microwave dielectric ceramics with high temperature stability were synthesized via conventional solid-state reaction. The influences of Co2O3 substitution on the phase composition, microstructure and microwave dielectric properties of ZMCxT ceramics were discussed. Rietveld refinement results show the coexistence of ZnTiO3 and ZnB2O4 phases at x = 0.02-0.10. (Zn0.9Mg0.1)1−xCoxTiO3 ceramic with x = 0.06 (ZMC0.06T) obtains the best combination microwave dielectric properties of: εr = 21.58, Q × f = 53,948 GHz, τf = − 54.38 ppm/°C. For expanding its application in LTCC field, 3 wt% ZnO-B2O3-SiO2 (ZBS) and 9 wt% TiO2 was added into ZMC0.06T ceramic, great microwave dielectric properties were achieved at 900 °C for 4 h: εr = 26.03, Q × f = 34,830 GHz, τf = − 4 ppm/°C, making the composite ceramic a promising candidate for LTCC industry.