Effects of BaO sintering additive on dielectric properties of Y ₂Ti ₂O ₇ microwave dielectric ceramics

Y ₂Ti ₂O ₇ ceramics of middle-permittivity doped with BaO sintering additive were investigated. Effects of BaO content on the sintering and dielectric properties were evaluated. Pyrochlore Y ₂Ti ₂O ₇ as the main phase and small amount of Ba ₄Ti ₁₃O ₃₀ as the second phase were detected by X-ray diffraction patterns (XRD). The sintering temperature decreased obviously with increasing BaO content. The permittivity (εr) of BaO-doped Y ₂Ti ₂O ₇ ceramics ranged from 54 to 40. Doping with 1 % BaO (mass fraction), the εr value was still over 50. The temperature coefficient of resonant frequency ( τf) had a trend to zero, especially when 5 % BaO doped, τf ≈ -7 ppm/°C. The results shows that Y ₂Ti ₂O ₇ ceramics with 1 % BaO addition sintered at 1330 °C exhibited excellent comprehensive performance: er ≈ 50.3, Q·f ≈ 5978 GHz, τf ≈ -27 ppm/°C. The ceramics doped with 1 % BaO should be a promising candidate for microwave resonators.