Investigations on Material and Mechanical Properties, Air-Permeation Behavior and Filtration Performance of Mullite-Bonded Porous SiC Ceramics

A theoretical relation between processing parameters and porosity (29-56%) of mullite-bonded porous SiC ceramics was derived and validated with experimental data. Porosity-dependent variation of fracture strength (9-34 MPa) and elastic modulus (7-28 GPa) was explained by the minimum solid area model. At room temperature, the Darcian, k(1) (1.2 x 10(-13)-1.6 x 10(-12) m(2)) and the non-Darcian, k(2) (4.6 x 10(-9)-2.7 x 10(-7) m) permeability coefficients showed linear variation with porosity. Tests conducted up to 650 degrees C indicated an increase in k(1) with temperature and a reverse trend for k(2). Airborne NaCl nanoparticle filtration tests showed good performance of SiC ceramics with fractional collection efficiency of >99% at 46-56% porosity levels.