Porous silicon nitride ceramics were prepared using an extrusion process. Starch and thermoset phenol-formaldehyde resin were used as binders. The effect of the different binders on the microstructure and mechanical strength of the porous silicon nitride were investigated in detail. It is shown that the microstructure was more uniform when phenol-formaldehyde resin was used as the binder. In contrast, the pore size distribution was bimodal when starch was used. Furthermore, the flexural strength of porous Si3N4 using resin as the binder was higher than that using the starch.

Keywords: Porous silicon nitride; Extrusion; Binders; Microstructure