Effect of glass composition on the densification and dielectric properties of BaTiO 3 ceramics

Abstract

An ongoing research goal of thick film capacitors and multilayer capacitors is to lower the firing temperature of the dielectrics. This paper presents the results of using three simple glass systems including PbO–B 2O 3, PbO–SiO 2, and Bi 2O 3–B 2O 3 as sintering aids for hydrothermal synthesized BaTiO 3. Glasses with different ratios of the modifier/glass former were employed. Effects of adding these glass systems on the BaTiO 3 ceramics sintered at 850°C were investigated through measuring and analyzing the density, grain size and dielectric property. It was found that BaTiO 3 sintered with glasses composed of 90 mol% PbO–10 mol% SiO 2 or 90 mol% PbO–10 mol% B 2O 3 to 60 mol% PbO–40% B 2O 3 are helpful to reduce the firing temperature for typical thick film and MLCC applications. They possess high dielectric constant (≈1650) due to their high densification characteristics with the grain size of ≈0.7 μm. In addition, glasses composed of 90 mol% Bi 2O 3–10 mol% B 2O 3 to 40 mol% Bi 2O 3–60 mol% B 2O 3 are beneficial for thin dielectric layer applications, on account of the high sintering density and a small grain size of ≈0.1 μm with an acceptable K value.