Wanwilai Chaisan

Two-Stage Sintering of Barium Titanate Ceramic and Resulting Characteristics

The potential of a two-stage sintering technique as a low-cost and simple ceramic fabrication to obtain highly dense and pure barium titanate ceramics with small grain size was demonstrated in this study. Effects of designed sintering conditions on phase formation, densification, microstructure, and electrical properties of the BaTiO 3 ceramics were examined via X-ray diffraction (XRD), Archimedes method, scanning electron microscopy (SEM), dielectric and hysteresis measurements, respectively. It has been found that, under suitable two-stage sintering conditions, the dense perovskite BT ceramics with fine grain can be successfully achieved with good electrical properties.

Changes in ferroelectric properties of barium titanate ceramic with compressive stress

In this work, barium titanate (BT) ceramic was prepared using a conventional mixed oxide method. The effect of uniaxial compressive stress on the ferroelectric properties of BT ceramics were investigated. The changes in ferroelectric properties were observed at stress up to 60 MPa using a compressometer in conjunction with a modified Sawyer–Tower circuit. The results showed that applied stress had a significant influence on the ferroelectric properties of BT ceramics. Ferroelectric characteristics, i.e. the area of the ferroelectric hysteresis (P–E) loop, the saturation polarization (Psat), the remanent polarization (Pr) and the loop squareness (Rsq), decreased with increasing compressive stress, while the coercive field (Ec) remained constant. Stress-induced domain wall motion suppression and non-180° ferroelectric domain switching processes are responsible for the changes observed.

A Two-Stage Solid-State Reaction to Lead Zirconate Titanate Powders

An approach to synthesize lead zirconate titanate (PZT) powders with a modified two-stage mixed oxide synthetic route has been developed. To ensure a single-phase perovskite formation, an intermediate phase of lead zirconate (PbZrO 3 ) was employed as starting precursor. The formation of perovskite phase in the calcined powders has been investigated as a function of calcination temperature. It has been found that the perovskite PbZrO 3 and PbTiO 3 phases tend to form together with PZT, with the latter appearing in both tetragonal and rhombohedral phases, depending on calcination temperatures. It is seen that optimization of calcination can lead to 100% yield of PZT phase.