Low Temperature Sintering of Ca[(Li_1/3Nb_2/3)_1-xTi_x]O_3-δ Based Microwave Dielectric Ceramics with Glass Frit

Abstract

The microstructures and the microwave dielectric properties of Ca[(Li 1/3 Nb 2/3 ) 1- x Ti x ]O 3-δ (CLNT) ceramics with different amount of glass frit additions were investigated. Addition of glass frit(B 2 O 3 –ZnO–SiO 2 –PbO system) improved the densification and decreased the sintering temperature from 1150°C to 900°C of Ca[(Li 1/3 Nb 2/3 ) 1- x Ti 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 · f 0 ), 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 1/3 Nb 2/3 ) 0.8 Ti 0.2 ]O 3-δ with 12 wt% glass sintered at 900°C for 3 h were ε r =40, Q · f 0 =12,500, τ f =-8 ppm/°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).