还原退火Sr_3Ti_2O_7织构陶瓷的结构和电性能

The Microstructure and Dielectric Properties of Textured Sr_3Ti_2O_7 Ceramics Annealed in Reducing Atmosphere

采用片状形貌的Sr3Ti2O7为模板籽晶,通过模板晶粒生长法(TGG)结合流延叠层烧结技术制备出晶粒择优取向的Sr3Ti2O7织构陶瓷,研究了还原气氛退火处理对于Sr3Ti2O7织构陶瓷微观组织结构的影响规律。结果表明,在1 500℃不同保温时间下制备的陶瓷主晶相均为Sr3Ti2O7,且有沿(00l)面择优取向晶粒形貌,其织构度随保温时间的延长呈增大趋势;将Sr3Ti2O7织构陶瓷在Ar气中退火处理后陶瓷中发生了相变,生成了新相Sr2TiO4,且Sr2TiO4含量随退火温度升高和退火时间延长而减少;退火处理后陶瓷的织构度减小;平行和垂直流延方向上介电常数存在各向异性,且退火处理后介电常数减小。

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 1 500 ℃ 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 Sr3Ti2O7 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.