Structural and Dielectric Properties of Ag(Nb 0.8 Ta 0.2 ) 1− x Sb x O 3 ( x ≤0.08) Ceramics

Sb 2 O 5 were selected to substitute (Nb 0.8 Ta 0.2 ) 2 O 5 and the effects of Sb substitution on the dielectric properties of Ag(Nb 0.8 Ta 0.2 )O 3 ceramics were studied. The perovskite Ag(Nb 0.8 Ta 0.2 ) 1− x Sb x O 3 ceramics showed no obvious change with x value being no more than 0.08, and the pseudoperovskite unit cell parameters a=c, b and monoclinic angle β decrease with Sb concentration increasing. The dielectric properties of Ag(Nb 0.8 Ta 0.2 ) 1− x Sb x O 3 ceramics were found to be affected greatly by the substitution of Sb for Nb/Ta. The ɛ value of Ag(Nb 0.8 Ta 0.2 ) 1− x Sb x O 3 ceramics sintered at their densified temperature increased from 480 to 825 with x from 0 to 0.08, the tan δ value decreased sharply from 0.0065 to 0.0023 (at 1 MHz) with x increasing from 0 to 0.04, and then kept a stable lower tan δ value ∼0.0024 with x to 0.08. The temperature coefficient of capacitance values continuously decreased from a positive value of 1450 ppm/°C for x =0 to a negative value of −38.52 ppm/°C for x =0.08.