Grain orientation and properties of SrBi₂Ta₂O₉ ceramics with excess Bi₂O₃

Abstract

The purpose of this paper is to investigate the grain orientation and properties of SrBi₂Ta₂O₉ (SBT) ceramics with excess Bi₂O₃. Ordinarily fired (OF) ceramics were prepared by conventional ceramic techniques at 900–1300°C for 2 h. The grain-oriented (GO) ceramics were prepared using the hot-forging method. With addition of Bi₂O₃ in the amount of 0 – 1.5 wt% to the SBT of stoichiometric composition, the optimum firing temperature in OF ceramic samples gradually lowered with increasing Bi₂O₃ addition, and was about 1100°C in the case of 0.5 wt% of excess Bi₂O₃. Plastic deformation is easily accomplished using the hot forging method where Bi₂O₃ exists as a state of liquid phase within the sample. In fact, the GO sample with 0.5 wt% of excess Bi₂O₃ showed a highly structured orientation f=0.97 in the case of hot-forging at 1100°C.

Keywords:

• SrBi₂Ta₂O₉
• Bi₂O₃
• ceramics
• grain orientation
• hot forging