Preparation and characterization of the three-dimensional network mullite porous fibrous materials by pressure and freeze-casting method

Porous fibrous materials (PFMs) with three-dimensional networks were prepared by mullite fibers as skeleton and silica sols as binder via pressure and freeze-casting method. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP) were used to investigate the microstructures, phase and porous characteristics. The density of PFMs can be controlled by adjusting the pressure and sintering during the synthetic process. With the increase of density, the mechanical and thermal conduction properties were increased due to densification of fibers. Based on their lightweight and low thermal conductivity, the PFMs can be used in the field of high temperature thermal insulation.