In situ inorganic foaming of ceramics

Aqueous based process for the production of alkali-bonded ceramic foams allows the tailoring of the porosity from the nano- to the ultra-macrometric range. In order to fulfil the porosity requirements for many different applications (thermal insulation, catalysis, filtration, biomaterials,etc.), porous 3D networks (foams) were prepared by inducing interconnected ultra-macro-porosity, up to the millimetre range, exploiting the ability of silicon powder to generate H2 in the alkali aqueous medium. Alumina and silicon carbide based foams were developed with this low temperature process, thus avoiding the sintering step. Alkali-bonded ceramic foams were thoroughly studied in order to optimize the consolidation process and to obtain the desired porosity. Ceramic foams were also fully characterized and the experimental findings highlighted the versatility of these foams, that may be properly tailored as a function of the possible final application.