Si3N4 with comparable permeability to SiC

Porous sintered reaction-bonded silicon nitrides (SRBSNs) with comparable permeability to SiC were fabricated using presintered Si-additive mixture granules. By increasing the granule strength through the adjustment of the presintering conditions, the strengthened sturdiness of the granules led to an increase in the pore channel size. Porous SRBSNs with ≥60% porosity were achieved without employing a pore former due to the formation of intragranular narrow pore channels as well as intergranular wide pore channels. As the specific pore area of the developed SRBSN is nearly 26 times that of SiC with similar permeability, superior filtering efficiency for nano-sized particulate matter is expected.