Influence of Bi_2O_3 addition on structure and dielectric properties of Ag(Nb_(0.8)Ta_(0.2))O_3 ceramics

摘要

The structure and dielectric properties of perovskite Ag(Nb_(0.8)Ta_(0.2))O_3 ceramics were explored. A small amount of Bi_2O_3 was used to modify the dielectric properties of the ceramics. The addition ofBi_2O_3led the ceramics to a high densification and optimal dielectric properties. With the addition of 4.5 wt% Bi_2O_3, the permittivity of Ag(Nb_(0.8)Ta_(0.2))O_3 ceramics increased from 470 to 733, the dielectric loss decreased from 62 × 10~(-4) to 6.7 × 10~(-4), and the temperature coefficient of capacitance, TCC, decreased from 2004 ppm/℃ to —50 ppm/℃. The high permittivity obtained was due to the high densification and weak Ta-O or Nb-O bond strength in the oxygen octahedron that results from the addition of Bi_2O_3.