Microstructure and Microwave Dielectric Properties of BaTi_4O_9 Ceramics Derived from a Sol-Gel Precursor

摘要

In the present work, the microstructure and microwave dielectric properties of BaTi_4O_9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (ε_r), quality factor (Q×f) and the temperature coefficients (τ_f) of the BaTi_4O_9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti~(3+) was proposed to be the cause of dielectric loss.