Properties of multiple oxide-bonded porous SiC ceramics prepared by an infiltration technique

Multiple oxide-bonded porous SiC ceramics were fabricated by infiltrating a porous powder compact of SiC and alumina with cordierite sol followed by sintering at 1300-1400°C in air for 3 hours. The microstructures, phase components, mechanical properties, and air permeation behavior of the developed porous ceramics were examined and compared with materials obtained by the traditional powder processing route. The porosity, average pore diameter, and flexural strength of the ceramics varied from 33 to 37 vol%, ~12-14 μm and ~23-39.6 MPa, respectively, with variation in sintering temperature. The X-ray diffraction results reveal that both the amount of cordierite and mullite as the binder increased with increase in sintering temperature. In addition, it was found that the addition of alumina in powder form effectively enhanced the strength due to formation of mullite in the bond phase in contrast to the samples prepared without alumina additive. To determine the suitability of the material in particulate filtration application, particle collection efficiency of the filter material was evaluated theoretically using single collector efficiency model.