Abstract
Cordierite/mullite composite filters (C:M=0.65:0.35 in molar ratio) with controlled pore structure were fabricated using starch powders as pore-forming agent. Preformed cordierite/mullite composite powders were mixed with different starch powders (10～50μm) to prepare water-based ceramic slurry. They were consolidated into homogenous green bodies by gelcasting. Subsequent firing at a controlled heating schedule produced porous composite ceramics via burn-out of starch powder. The porosity of specimens could be controlled by adjusting the mixing ratio of starch powders and by sintering temperature. With a maximum starch content of 35mass%, the porosity of the C/M composites were found to be 67.7% and 58.3% after sintering at 1350°C and 1400°C, respectively. The porous composites consisted of the smaller intergranular pores and the larger ones derived from starch powder. The ratio of the larger pores to the smaller ones in these composite filters was estimated to be about 40:60.
