Effects of additives on the sintering temperature and dielectric properties of ZnTIO_3 based ceramic

摘要

The effects of various additives, namely ZnO-B_2O_3-SiO_2 (ZSB), B_2O_3 and B_2O_3 + LiF on the lowering of sintering temperature and dielectric properties of ZnTiO_3 based ceramics were investigated. From the dilatometric studies, it was shown that the sintering temperature is significantly lowered owing to the addition of 15 mol. percent of ZSB or of the addition of 15 mol. percent of B_2O_3: ZSB added sample can be sintered at 950 deg C and B_2O_3 added one at 1000 deg C whereas pure compound hence can be sintered at 1100 deg C. The most interesting result concerns the ZSB added sample sintered at 950 deg C during 4 h which exhibits a density higher than 92 percent of the theoretical one, high dielectric constant (epsilon_r approx = 25) and low dissipation factor (tan(delta) < 10~(-3)) in the range -60 deg C/160 deg C at 1 MHz. The temperature coefficient of the dielectric constant is also reasonable (epsilon approx = -150 ppm/DC) as well as the temperature coefficient of the resonant frequency (|tau_f| < 100ppm/ deg C). This formulation should be consequently a suitable candidate for low-temperature co-fired ceramics (LTCCs).