The Effect of PVA Binder Solvent Composition on the Microstructure and Electrical Properties of 0.98BaTiO3-0.02(Ba0.5Ca0.5)SiO3 Doped with Dy2O3

Abstract

In this study, the effect of the polyvinyl alcohol (PVA) binder solvent composition on the electrical properties of sintered 0.98BaTiO3-0.02(Ba0.5Ca0.5)SiO3 ceramics doped with x wt.% Dy2O3 (0.0 ≤ x ≤ 0.3) was investigated. In the absence of the PVA binder, the specimens sintered at 1260 and 1320 °C for 1 h in a reducing atmosphere showed a single BaTiO3 phase with the perovskite structure. The relative densities of the specimens were higher than 90%, and the grain morphologies were uniform for all the solvent compositions. At 1 kHz, the dielectric constant of the specimens depended not only on their crystal structural characteristics, but also on their microstructural characteristics. The microstructural characteristics of the specimens with the PVA binder were affected by the ethyl alcohol:water ratio of the 10 wt.% PVA-111 solution. A homogeneous microstructure was observed for the 0.1 wt.% Dy2O3-doped specimens sintered at 1320 °C for 1 h when the ethyl alcohol/water ratio of the binder solution was 40/60. These specimens showed the maximum dielectric constant (εr = 2723.3) and an insulation resistance of 270 GΩ. The relationships between the microstructural characteristics and dissipation factor (tanδ) of the specimens were also investigated.