Low Temperature Sintering of Ba₂Ti₉O₂₀ Dielectric Ceramics with GeO₂ and B₂O₃ Additives

Abstract

Ba₂Ti₉O₂₀ with GeO₂ and B₂O₃ was synthesized by an ordinary sintering method. Fired densities, dielectric constants and dielectric losses were measured. Ba₂Ti₉O₂₀ containing B₂O₃ sintered at lower temperatures and Ba₂Ti₉O₂₀ containing GeO₂ showed more excellent dielectric properties than a single phase of Ba₂Ti₉O₂₀. However, Ba₂Ti₉O₂₀ containing GeO₂ and B₂O₃ showed no improvement in the sinterability and dielectric properties by low temperature firing. A two-step addition process, i.e., separate addition of GeO₂ and B₂O₃ before and after the calcination, respectively, was effective in reducing the firing temperature without affecting the dielectric properties. XRD (X-ray diffraction) analysis and SEM (scanning electron microscope) observation were carried out on those samples. The sintering mechanism of Ba₂Ti₉O₂₀ containing GeO₂ and/or B₂O₃ was proposed and the relationship between the microstructures and dielectric characteristics was discussed.