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.