Investigation of Gel Casting Preparation of Micro-Porous Si3N4 Ceramics

Gel casting preparation of porous Si3N4 ceramics by merely increasing monomer content in the slurry without other organic additives was investigated. High performance porous Si3N4 ceramics were obtained, and the flexural strength and porosity were over 137 MPa and over 50%, respectively. The median pore diameter of porous Si3N4 ceramics is less 1 mu m. The experimental results shows that: increasing monomer content makes the porosity of porous Si3N4 ceramics monotonically increase; the porosity of porous Si3N4 ceramics monotonically decreased with increasing solid loading, and the solid loading had an optimum value for the flexural strength which achieved maximum strength; with sintering temperature, the flexural strength monotonically increases, but the porosity monotonically decreases.