Self-setting particle-stabilized foams with hierarchical pore structures

Abstract

This study presents a novel method to produce self-setting inorganic foams with unique hierarchical pore structures. The combination of particle-stabilized alumina foams with calcium aluminate cement leads to a macroporous ceramic material which can be shaped and consolidated at room temperature, bypassing the challenging and sometimes extensive drying and sintering steps. Due to the water consuming cement hydration reaction, no macroscopic shrinkage was observed and crack and cavity formation was prevented throughout the entire specimens. The final microstructure features a porosity of 76 vol.% and a unique hierarchical pore structure with interconnecting pores of 200 µm diameter, separated by mesoporous pore walls. The authors believe that this newly developed method opens a door to novel applications where so far the drying and sintering step and its inherent shrinkage of the ceramic foams were the limiting factors.