Preparation and characterization of SiC/cordierite composite porous ceramics

摘要

SiC/cordierite composite porous ceramics were prepared by a reactive process, in which clay, talc and alumina were mixed with 'SiC powder and graphite was used as the pore former. The mixture was heated in air so that graphite was burned out and SiC particles were bonded by reaction-derived cordierite. The sintering temperature was chosen as 1360 deg C according to DTA and XRD studies. The volume fraction of graphite had a strong influence on porosity and strength. A three-point bending strength of 54.6 MPa was achieved at a porosity of 27.6 percent, while the strength of 9.3 MPa was corresponding to a porosity of 59.6 percent. Moreover, as-prepared composite porous ceramics exhibited excellent resistance to cyclic thermal shock.