The microstructure and dielectric properties of textured Sr₃Ti₂O₇ ceramics annealed in reducing atmosphere

Using plate-like Sr₃Ti₂O₇ particles as templates, textured Sr₃Ti₂O₇ ceramics of orientated grains were fabricated by Templated Grain Growth (TGG) technique combining with tape casting method. The effects of the microstructure of textured Sr₃Ti₂O₇ ceramics annealed in reducing atmosphere Ar were investigated. The results showed that the main crystalline phase of the ceramics sintered at 1500°C for different soaking times were Sr₃Ti₂O₇, the preferred orientation of the grain morphology was along (00l) crystal plane, of which the texture fraction increased with the increasing of soaking times. Phase transformation occurred on the surface of the textured Sr₃Ti₂O₇ ceramics annealed in Ar atmosphere, generating a new phase Sr₂TiO₄. With the increase of the annealing temperature and annealing time, the content of Sr₂TiO₄ decreased. The texture fraction degraded after the annealing. The dielectric constant parallel and perpendicular to the tape casting direction showed anisotropy and the dielectric loss decreased after annealing.