Ice-templated porous alumina structures

TL;DR

This paper presents a method to create regular, multilayered porous alumina structures by controlling ice formation during freezing of ceramic slurries, enabling tailored architectures for various applications.

Contribution

It introduces a novel ice-templating process for producing well-defined porous alumina with controlled architecture and discusses the underlying physics of ice solidification affecting structure formation.

Findings

Regular multilayered porous alumina structures were successfully fabricated.

The morphology of the structures is influenced by ice interface kinetics.

Potential applications include filters, biomaterials, and multilayered composites.

Abstract

The formation of regular patterns is a common feature of many solidification processes involving cast materials. We describe here how regular patterns can be obtained in porous alumina by controlling the freezing of ceramic slurries followed by subsequent ice sublimation and sintering, leading to multilayered porous alumina structures with homogeneous and well-defined architecture. We discuss the relationships between the experimental results, the physics of ice and the interaction between inert particles and the solidification front during directional freezing. The anisotropic interface kinetics of ice leads to numerous specific morphologies features in the structure. The structures obtained here could have numerous applications including ceramic filters, biomaterials, and could be the basis for dense multilayered composites after infiltration with a selected second phase.