Novel method of fabricating ultra-light aluminum borate foams with hierarchical pore structure

Abstract Ultra-light aluminum borate foams (ABFs) with porosity ranging from 92.18 to 86.82 vol% were fabricated by combining foam-casting and freeze-drying using alumina and boron carbide as raw materials. The effects of heating temperature on phase evaluation and the influence of solid content of slurries on the physical properties and formation mechanism of the three-dimensional interconnected hierarchical pore structure in ABFs were investigated. The contacting of bubbles, burning loss of organics, replacement of ice crystals by alcohol, and interlocking of rod-like aluminum borate crystal together created a hierarchical pore structure in foams. The results revealed that the performance and microstructure of ABFs could be controlled by adjusting the solid content of slurries.