Fabrication of Porous Alumina Ceramics by Freeze-Casting Technique

Porous ceramics with complex pore structure were synthesized by freeze-casting process.The major factors affecting the microstructure of the porous ceramic were discussed.The results show that the porous structures can be controlled and maintained quite well during the drying and firing processes,the porosity and the strength are substantially affected by the starting slurry concentration,the adhesive is important for keeping the main structures,and sintering temperature has directly influence on finally pore size distribution and the microstructure.Taking sodium silicate as binder,the mechanical strength of porous ceramics markedly increase,but this has affact on the porosity,so just adding a little of it can increase the porosity,when the quantity exceeds 30%,the porosity and aperture decreases,whereas the compression strength increases.