Enhancing the densification process on Ba(Mg1/3Ta2/3)O-3 microwave dielectrics by Y2O3 incorporation

The relative density of Ba(Mg1/3Ta2/3)O-3 (BMT) has been found to significa ntly increase due to the addition of Y2O3. A sintering condition of 1650 de grees C (4 hrs) is necessary to densifie the undoped BMT specimens to 95% t heoretical density (T.D.), while relatively lower sintering temperature, 14 50 degrees C (4h), is sufficient to densify the BMT materials containing 6 mol% Y2O3 to 95% TD. However, the Q.f-value of Y2O3-doped materials increas es monotonously with sintering temperature and reaches a maximum value (Q.f =650000) when 1600 degrees C (4h) sintered. Microwave dielectric properties of the 1600 degrees C -sintered BMT samples also increase with Y2O3-conten t. High Q.f value of the samples is intimately correlated with their large ordering factor (S). The temperature coefficient of resonant frequency (tau (f)) of these samples is tau(f)=13.2ppm/degrees C for the temperature rangi ng from 25 to 80 degrees C.