Ceramics-Silikáty 59, (4) 348 - 352 (2015)

Porous alumina ceramics with different porosity were fabricated by combining the starch consolidation process with the gel-casting process using corn starch as a pore-forming agent and a binder. The bulk density, porosity, and microstructure of the obtained alumina ceramics were studied. It was found that the total porosity range of sintered samples with contents varying from 0 to 50 vol. % is 14.8 - 55.3 % and the total porosity increased with the increase of starch content. Moreover, a relationship between the total porosity of alumina ceramics after sintering and corn starch content was obtained. This relationship indicates that the total porosity of alumina ceramics fabricated in this work was higher than that of the ceramics made by traditional slip-casting. The range of total porosity of ceramics in this work was broader than that of the ceramics produced by starch consolidation casting. The relation between the linear shrinkage of porous alumina ceramics and the starch content also was discussed. The compressive strength of the sintered samples varied within the range of 5 - 24 MPa, corresponding to starch content of 50 - 10 vol. %.