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Porous materials with wrinkled surfaces could have broad applications in catalysis and adsorption. However, designing cellular ceramics with similar structures is challenging. Herein, we demonstrated the binary colloidal self-assembly of γ-Al 2 O 3 nanoparticle/silica gelation network for constructing such materials. The competitive effect between volume shrinkage and surface bend during water evaporation of silica gel contributed to wrinkled aperture surface. During calcination, silica nanoparticles were highly active to react with alumina to form mullite nanocrystals, bringing about high compressive strength at low relative densities. After calcining at 1350 °C, resultant products with hierarchical structure exhibited an outstanding compressive strength of 4.2 MPa, a relatively high surface area of 7.23 m2/g at a porosity level of 83.3%. The current strategy provides a feasible and affordable approach for producing high performance ceramic foams towards practical application fields in catalysis and adsorption. [ABSTRACT FROM AUTHOR]

Abstract In the present work, Al 2 O 3 -Si 3 N 4 porous ceramics with a cactus-like architecture were fabricated by calcining Al 2 O 3 -Si binary particle-stabilized foams in the nitrogen atmosphere. A large number of acicular Si 3 N 4 nanobelts were constructed on the surface of cell walls as a consequence of CVD process to achieve an interlaced network. Such structure was beneficial to realize a high capture efficiency of particulate matters (PM) during filtration. Resultant products having a bulk density of 0.38 g/cm3 at an apparent porosity of 86% can potentially be applied as the air filters in environment field. [ABSTRACT FROM AUTHOR]

Compressive strength is one of the most important mechanical properties for ceramic foams but the dependence of compressive strength of highly porous ceramic foams on porosity remains unclear up to now, especially for the ceramic foams with porosity above 94%. In this paper, the relationship between compressive strength and porosity of ceramic foams with high porosity in the range of 79–98% was studied for the first time. The alumina ceramic foams and zirconia foams were prepared by particle-stabilized foaming method using sodium dodecyl sulfonate (SDS) as foaming agent. It was found that the function relation between compressive strength and porosity depended on porosity level. Specifically, compressive strength of ceramic foams fitted well with Rice Model when the porosity ranged from 79% to 94%. When the porosity increased above 95%, compressive strength of ceramic foams showed linear relation to porosity, which was probably due to the characteristic of highly porous ceramic foams with thin and lamellate cell wall. [ABSTRACT FROM AUTHOR]