Effect of B2O3-Bi2O3-SiO2-ZnO glass on the sintering and microwave dielectric properties of 0.83ZnAl2O4-0.17TiO2

The 0.83ZnAl{sub 2}O{sub 4}-0.17TiO{sub 2} (ZAT) ceramics were synthesized by solid state ceramic route. The effect of 27B{sub 2}O{sub 3}-35Bi{sub 2}O{sub 3}-6SiO{sub 2}-32ZnO (BBSZ) glass on the microwave dielectric properties of ZAT was investigated. The crystal structure and the microstructure of the ceramic-glass composites were studied by X-ray diffraction and scanning electron microscopic techniques. The low frequency dielectric loss was measured at 1 MHz. The dielectric properties of the sintered samples were measured in the microwave frequency range by the resonance method. Addition of 0.2 wt% of BBSZ improved the dielectric properties with quality factor (Q{sub u} x f) > 120,000 GHz, temperature coefficient of resonant frequency ({tau}{sub f}) = -7.3 ppm/deg. C and dielectric constant ({epsilon}{sub r}) = 11.7. Addition of 10 wt% of BBSZ lowered the sintering temperature to about 950 deg. C with Q{sub u} x f > 10,000 GHz, {epsilon}{sub r} = 10 and {tau}{sub f} = -23 ppm/deg. C. The reactivity of 10 wt% BBSZ added ZAT with silver was also studied. The results show that ZAT doped with suitable amount of BBSZ glass is a possible material for low-temperature co-fired ceramic (LTCC) application.