Effects of alcohol additives on pore structure and morphology of freeze-cast ceramics

The porous alumina ceramics with lamellar structure were fabricated successfully by freeze casting. The viscosities of alumina slurries, pore structures, porosities and mechanical properties of the sintered ceramics were investigated by introducing both types of alcohols as water solidification modifier into the initial slurries, such as ethanol and 1-propanol. With the addition of ethanol or 1-propanol, the viscosities of slurries increased and porosities of sintered ceramics decreased. The compressive strengths of the sintered porous alumina ceramics were improved due to a good connectivity between lamellae with the addition of both types of alcohols. The lowest porosities of 68.52% and 73.72% and highest compressive strengths of 18.2 MPa and 15.0 MPa were obtained by the addition of 30% ethanol in mass fraction and 1-propanol, respectively.