Sintering Behavior and Dielectric Properties of Bi 3 NbO 7 Ceramics Prepared by Mixed Oxides and High‐Energy Ball‐Milling Methods

The sintering behavior and dielectric properties of Bi 3 NbO 7 ceramics prepared by the high‐energy ball milling (HEM) method and conventional mixed oxides method with V 2 O 5 addition were investigated. All the samples were sintered between 840° and 960°C. For the ceramics prepared by the mixed oxides method, the pure tetragonal Bi 3 NbO 7 phase formed without any cubic phase. With changing sintering temperature, the dielectric constant ɛ r lies between 79 and 92, while the Q × f values are between 300 and 640 GHz. The samples sintered at 870°C have the best microwave dielectric properties with ɛ r =79, Q × f =640 GHz, and the temperature coefficients of resonant frequency τ f between 0 and −20 ppm/°C. For the ceramics prepared by the HEM, a pure cubic phase was obtained. The ɛ r changes between 78 and 80 and Q × f were between 200 and 290 GHz.