Fabrication and sintering densification behavior of (Sr_{1_x}Pb_x) TiO₃ nano-powder

A series of (Sr_1-xPb_x)TiO₃ ceramic powders were prepared through chemical coprecipitation process. The calcining temperature of coprecipitation products was analyzed and determined according to differential thermal and thermogravimetric analysis (DTA-TG). X-ray diffractometry (XRD) results showed that, the coprecipitation products are nearly in amorphous state, which crystallized during calcining. The major phase is cubic (Sr_1-xPb_x)TiO₃ solid solution, and the minor phase, tetragonal PbTiO₃, extricates from the solid solution with increasing Pb content. The calcined (Sr_1-xPb_x)TiO₃ powders exhibit nanometer crystal grains and nanometer particles whose mean sizes are 20-30 nm and 20-50 nm, respectively. The particles exist in irregular global shape and in agglomerated state. The major agglomerated particles' mean size is 200 nm, and the minor ones' mean size is 750 nm. The sintering temperature decreases obviously, and at 1150°C the ceramics is nearly densified. The crystal structure of sintered ceramics has changed from cubic to tetragonal, and no extricated PbTiO₃ but ferroelectric domains exist in sintered ceramics.