Effects of silver addition on microstructure and electrical properties of barium titanate ceramics

Barium titanate-silver composites were prepared by using a solid state reaction process with silver contents ranging from 0 mol% to 20 mol%. XRD results and Raman spectra indicated that there was no phase other than BaTiO₃ and Ag in the ceramics and tetragonality of barium titanate reduced with increasing Ag content. SEM images illustrated that Ag influenced densification and microstructure of BaTiO₃ ceramics. Besides, addition of Ag led to increase in dielectric permittivity and broadening of ferroelectric-paraelectric phase transition peak. Also addition of Ag had effects on dielectric loss and dc conductivity. Dielectric and conductivity properties as a function of Ag volume fraction were explained by the percolation theory.