Open-Porous Silicon Nitride-Based Ceramics in Tubular Geometry Obtained by Slip-Casting and Gelcasting

Owing to its unique properties, silicon nitride is a frequently used materials choice in highly demanding applications in terms of thermal and mechanical load. In this work, porous silicon nitride-based support materials in hollow-tube configuration are generated through colloidal forming, and their respective properties for potential applications in the fields of membrane-based separation, filtration, or catalysis are evaluated. Shaping of the ceramics is achieved by two distinct casting techniques, slip-casting, and gelcasting, and the results of the respective methods are set in relation, Furthermore, a special focus is set on the correlation between sintering parameters and resulting porosity. Subsequently, air permeabilities of the generated structures are determined, illustrating a direct relation between processing parameters and resulting permeability. Darcian permeability values of up to 9-10(-16) m(2) are observed for samples exhibiting total porosities between 32 and 41 %. The findings allow for a predictability of suitable permeation properties for the structures' anticipated application as complex-shaped non-oxide ceramic supports for membrane-based separation or catalysis, or as high-performance filter materials.