Permeability Enhancement in Porous-Sintered Reaction-Bonded Silicon Nitrides

Pressure drop across filter materials is critical for the effective performance of various kinds of filtering system. To evaluate the feasibility of lowering the pressure drop of porous sintered reaction-bonded silicon nitrides, permeability tests were conducted for specimens with different porosity and pore structure. The results showed that pore former size is a minor factor, while permeability (κ) had a strong dependency on the amount of pore former. Prolonged sintering time (2 h vs 10 h at 1700°C) increased the permeability by increasing the effective pore diameter, which compensates for the observed decrease in total porosity.