Pore structure control of starch processed silicon nitride porous ceramics with near-zero shrinkage

Abstract

Zirconium phosphate (ZrP 2O 7) bonded silicon nitride (Si 3N 4) porous ceramics were prepared using starch powder as the pore forming agent and pressureless sintering technique. The obtained results show that the porosity of the sintered starch processed 25 wt.% ZrP 2O 7 bonded Si 3N 4 porous ceramics is 36–62.3%. All the samples exhibit surprisingly low linear shrinkage. The pores are formed by the continuous reaction of ZrP 2O 7 at ~ 250 °C and burnout of starch at ~ 550 °C, during which a large amount of pores with pore sizes of less than 0.5 μm and ~ 10 μm are formed.