Synthesizing of Platelike {100} SrTiO3 Particle by Topochemical Microcrystal Conversion Method

Cubic perovskite-structured platelike SrTiO₃ particles were synthesized by topochemical microcrystal conversion (TMC) method from platelike precursor of layer-structured SrBi₄Ti₄O₁₅ particles. SrTiO₃ particles inherited the shape of precursor particles having a thickness of about 0.5 microns and a width of 5-10 microns. X-ray diffraction measurement of cast particles on glass substrate elucidated that in the TMC reaction, the crystallographic {001} plane of SrBi₄Ti₄O₁₅ is converted into the {100} plane of SrTiO₃. With use of the platelike SrTiO₃ particles as a template by templated grain growth method, dense {100} grain-oriented SrTiO₃ ceramics having a {100} orientation degree (Logerring's factor) larger than 91% were fabricated at sintering temperatures between 1350degC to 1550degC. The maximum orientation factor was 99.3%. The textured ceramics had a unique microstructure of well aligned brick wall-like grains in the side face to tape-cast plane observed by scanning electron microscopy.