Low temperature sintering of Ca[(Li_1/3Nb_2/3) _1-xTi_x]O_3-δ based microwave dielectric ceramics with glass frit

The microstructures and the microwave dielectric properties of Ca[(Li _1/3Nb_2/3)_1-xTi_x]O _3-δ (CLNT) ceramics with different amount of glass frit additions were investigated. Addition of glass frit(B₂O ₃-ZnO-SiO₂-PbO system) improved the densification and decreased the sintering temperature from 1150°C to 900°C of Ca[(Li _1/3Nb_2/3)_1-xTi_x]O _3-δ microwave dielectric ceramics. The dielectric constants (ε_r) and bulk density were increased, as increasing glass contents from 10 wt% to 15 wt%. The quality factor (Q · f₀), however, was decreased slightly. The temperature coefficients of the resonant frequency (τ_f) shifted positive value as glass contents were increased. The dielectric properties of Ca[(Li_1/3Nb _2/3)_0.8Ti_0.2]O_3-δ with 12wt% glass sintered at 900°C for 3h were ε_r = 40, Q · f₀ = 12,500, τ_f = -8ppm/°C, respectively. The relationship between the microstructure and dielectric properties of ceramics was studied by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM).