Porous Alumina Ceramic Prepared by HEMA-TBA Gelcasting System

Porous alumina ceramics with high porosity and high strength were successfully fabricated by HEMA-TBA gelcasting system. Fabrication processes of slurries and ceramic were studied, effects of solid loading and dispersant contents on viscosity and stability of slurries, effects of drying and monomer content on green bodies, and effects of solid loading and sintering temperature on sintered bodies were investigated. The results show that optimum addition of citric acid of 2wt% decreases the viscosity and increases the stability of slurry. The viscosity and stability of the slurries increase with the increase of the solid loading of slurries. Green bodies with low solid loading can be dried with relatively small shrinkage less than 10% and its drying time is also relatively shorter than water based gelcasting system. The amount of monomer has great influence on green body and the strength of green body achieve high value at monomer content of 25%. By choosing the solid loading of slurries and sintering temperatures, ceramic microstructures and the porosity ranging from 40%-65% can be effectively controlled and strength of porous ceramics changes in the range of 5.7-91.2 MPa.