Fabrication of porous Ba(Ti,Sb)O3 ceramics and electrical properties

Ba(Ti,Sb)O3 ceramics containing potato-starch were prepared by sintering at 1350 °C for 1 h in air. The effect of potato-starch on the microstructure and electrical properties of Ba(Ti,Sb)O3 ceramics was investigated. The porosity and pore size increased and the grain size slightly decreased with increasing potato-starch content. The porosity and grain size of the Ba(Ti,Sb)O3 ceramic without potato-starch were 7.2% and 4.8 μm, respectively, while those were 30.7% and 3.5 μm, respectively, for the ceramic with 15 wt.% potato-starch and the average pore sizes of the samples with 10 and 20 wt.% potato-starch were 0.25 and 0.72 μm, respectively. All the Ba(Ti,Sb)O3 ceramics without and with potato-starch developed the PTCR characteristics in which the PTCR jump of the samples containing potato-starch was over 106 which is 1–2 orders higher than that of samples without potato-starch. The electrical properties of the Ba(Ti,Sb)O3 ceramics were discussed on the basis of microstructure, resistivity of grain boundaries, donor concentration of grains and the electrical potential barrier of grain boundaries.