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

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