Microstructures and dielectric properties of Ba[(Co0.7Zn0.3)1/3Nb2/3]O3-based ceramics prepared by aqueous gelcasting-assisted solid-state method

The aqueous gelcasting-assisted solid-state method (AGAS) and traditional solid-state reaction method (TSSR) were used to prepare Ba[(Co 0.7 Zn 0.3 ) 1/3 Nb 2/3 ]O 3 (BCZN)-based ceramics. The effects of different powder-preparation methods on the microstructures and dielectric properties of the BCZN-based ceramics were investigated. X-ray diffraction analysis showed completely the same phase compositions regardless of the preparation method adopted. The relative permittivity ( ε r ) did not significantly vary between the two methods. However, BCZN with CeO 2 -added ceramics prepared by AGAS had higher and more uniform density (6.374 g/cm 3 ) and high quality factor of resonant frequency ( Q × f ) value (75,843 GHz) than those prepared by TSSR because of the more uniform microstructures, as shown by scanning electron microscopy images. The temperature coefficients of resonant frequency ( τ f = 7.4 ppm/°C) of the ceramics prepared by AGAS were also closer to zero than those prepared by TSSR.