Effect of Silver Addition on the Dielectric Properties of Barium Titanate-Based X7R Ceramics

Different amounts of silver (0.5–10 wt%) have been mixed with EIA X7R-type ceramic powders based on barium titanate. The XRD analysis indicated that no phases other than BaTiO₃ and silver were present in the doped ceramics; it further suggested that no reaction took place between BaTiO₃ and silver during calcination and sintering. SEM observation showed that the silver particles presented island distribution in the BaTiO₃ ceramic matrix. The densification and dielectric properties of the silver-doped ceramics in disk form were investigated. A large amount of silver addition (>1 wt%) was found to improve the sintered density and dielectric properties. The temperature coefficient of capacitors of the ceramics doped with 10 wt% silver still met the X7R characteristics, and the dielectric constant of the ceramics at room temperature was >6000, which is the highest dielectric constant in the BaTiO₃-based X7R system.