Investigations of ice-structuring agents in ice-templated ceramics

The freeze-cast ceramics process involves the use of an aqueous slurry in which ice acts as a fugitive template, providing control of the morphology of the resultant green body, which is then sintered. Here we report the role of various additives and procedures in tailoring the morphology of ice-templated, freeze-cast alumina ceramics. We show that zirconium acetate (ZrAc) in the slurry can change the structure from lamellar to columnar, whereas polyvinyl alcohol can act as both a binder and as a modifier of the ice surface, and can compete with ZrAc to provide cooperative effects and a wide range of porosities. We also show that the ceramic structure can be influenced by epitaxial growth on an oriented layer of ice.