Extrusion of ceramic emulsions: Preparation and characterization of cellular ceramics

• Extruded bodies present good microstructural stability after sintering process.
• The bodies present mechanical strength until 30 MPa, permeability of 3 × 10− 4 m s− 1.
• Thermal conductivity lower than 0.25 W m− 1 K− 1.
• The obtained properties are framed with representative applications.

Recently, much effort has been given to development and/or optimization of porous materials with requirements for intended applications in catalysis, filtration, isolation, etc. In this context, this paper presents processing conditions and the correspondent characterization of cellular ceramics processed by extrusion of ceramic emulsions, obtained by emulsification of red clay, kaolin and alumina suspensions, after sintering at different temperatures. The emulsification of the ceramic suspension in paraffin with a melting point higher than room temperature is the key for the success of this processing method due to the freezing of the organic droplets allowing good stability of matrix during the extrusion process. Experimental results show good microstructural stability, yielding cellular ceramics with mechanical strength up to 30 MPa, permeability up to 3 × 10− 4 m s− 1, and thermal conductivity lower than 0.25 W m− 1 K− 1, framed with mentioned applications.