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

Zirconium phosphate (ZrP2O7) bonded silicon nitride (Si3N4) 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.% ZrP2O7 bonded Si3N4 porous ceramics is 36-62.3%. All the samples exhibit surprisingly low linear shrinkage. The pores are formed by the continuous reaction of ZrP2O7 at similar to 250 degrees C and burnout of starch at similar to 550 degrees C, during which a large amount of pores with pore sizes of less than 0.5 mu m and similar to 10 mu m are formed. (C) 2011 Elsevier B.V. All rights reserved.