Sintering behavior, phase evolution, and microwave dielectric Ppoperties of Bi(Sb_1-xTa_x)O₄ ceramics

Sintering behavior, phase evolution, and microwave dielectric properties of Bi(Sb_1-xTa_x)O₄ ceramics (0.05≤x≥0.60) were studied and their relationships were discussed in detail. Phase studies revealed that a pure monoclinic phase could be formed when x≤0.20 and a pure orthorhombic phase could be obtained when x≥0.50. As the x value increased from 0.05 to 0.60, the densified temperature of Bi(Sb1 xTax)O4 ceramics decreased from 10501 to about 9601C whereas the density increased from 8.07 to 8.41 g/cm3. The microwave dielectric constant increased from 20.5 to 34 whereas the Q ×f value decreased from 60 000 to 29 000 GHz. In the monoclinic phase region, the temperature coefficients of resonant frequency shifted linearly from -58 to -45 ppm/°C as the x value increased from 0.05 to 0.2 and then remained constant at about -12 ppm/°C when x≥0.40. The Bi(Sb_1-xTa_x)O₄ ceramics are promising for application of lowtemperature cofired ceramics technology.