Preparation of SrTiO_3 Ceramic Foam from Alkoxide-Derived Oxide Green Sheets Containing Polymer Microspheres via Polymer Extraction (Part 2)-Influence of Additional Amount of Polymer Microsheres on SrTiO_3 Ceramic Foam

摘要

SrTiO_3 ceramic foams with spherical pores were obtained by polymer extraction from oxide green sheets containing polymer microspheres. Fine SrTiO_3 particles were prepared by hydrolysis of Sr (OC_3H_7~i)_2 and Ti (OC_3H_7~i)_4, and were well-dispersed by oily alkylbenzensulfonate type ainonic surfactant. Size and morphology of polymer spheres were reflected in pores of green sheets. Five kinds of the green sheets with various weight ratios of SrTiO_3 to polystyrene microspheres, 100/0, 100/50, 100/100, 100/150 and 100/200, were prepared. The polystyrene microspheres were extracted by benzene, and heat-treated at 1300 deg C. Linear shrinkage of the green sheets observed during the heat treatment increased from 31.1 percent to 41.2 percent with increasing of the polystyrene microsphere content. Porosity of the SrTiO_3 ceramic foams changed from 3.7 percent to 74.0 percent with the adding amount of polystyrene microspheres. Closed pore structures of the SrTiO_3 ceramic foam were transformed into open pore structures with the increase of the polystyrene microsphere content.