Starch consolidation of porous fused silica ceramics

Starch consolidation is a forming technique, in which ceramic suspension is consolidated by gelatinization of starch under suitable temperature. This technique is promising for fabricating porous ceramics because starch can act as a binder as well as a pore former. In this study, porous fused silica ceramics were prepared by starch consolidation using glutinous rice flour as a gelling agent. The 29 vol% solid loading of fused silica slurries with the addition of glutinous rice flour were prepared. After mixing the slurries were poured into a plastic mold and kept in an oven at 75 degrees C for an hour. The green samples were dried and sintered at a temperature range of 900-1300 degrees C for an hour. Bulk density and compressive strength of the fused silica ceramics with 7 wt% glutinous rice flour sintered at 1150 degrees C were 1.26 g/cm(3) and 13.33 MPa, respectively. The phase of the sintered specimens remained amorphous with very low thermal expansion coefficient of 0.58 x 10(-60) C-1.