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

• Published in: Advanced engineering materials Vol. 19; no. 10
• Main Authors: Brouczek, Dominik, Konegger, Thomas
• Format: Journal Article
• Language: English
• Published: 01.10.2017
• Subjects: colloidal processing; gelcasting; porosity; silicon nitride; slip‐casting
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201700434

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 m2 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. Two distinct colloidal‐based casting approaches (slip‐casting and gelcasting) are evaluated for the generation of porous Si3N4 ceramics in tubular geometry, suitable for prospective applications in the fields of separation or catalysis. Partial sintering facilitates tightly controllable pore morphologies, thus allowing for a direct correlation between processing, porosity, and permeability characteristics of the tubular structures prepared.