Preparation and Properties of Low-Temperature Sintered SrBi₄Ti₄O₁₅/Ag Composites

Strontium bismuth titanate (SBTi) matrix composites containing Ag particles were synthesized by the conventional solid-state reaction method. The SBTi/Ag composites have been characterized by various techniques: x-ray diffraction, optical metallurgical microscope, scanning electron microscope and dielectric measurement. It is found that Ag doping significantly affect the physical properties of composites. By adding Ag particles to the SBTi matrix, the single-phase layered perovskite structure of the matrix is preserved and the sintering temperature of the system decrease from 1120°C of the single-phase SBTi to 950°C of the SBTi/Ag composites. With the increase of sintering temperature, the size of silver particles increase, but the SBTi grains have no significant growth. The SBTi/Ag composites show a significant change of the dielectric constant. By increasing Ag content, a gradual increase of the dielectric constant is observed and the dielectric loss of the SBTi/Ag composites remain unchanged when the temperature rangers from room temperature to 200°C, however, the Curie peak of dielectric constant is repressed, which has been interpreted based on the effective dielectric fields developed around conducting phases and the inhibition effect of nonferroelectric secondary phase to electro-strain.