Filtering Properties of Porous Ceramics with Unidirectionally Aligned Pores.

Among porous ceramic with unidirectionally aligned pores, synthesized from a water-based slurry using unidirectional freezing and freeze-drying process, porous silicon nitride showed a characteristic microstructure wherein the macroscopically aligned open pores contained many fibrous grains protruding from their internal walls. Pressure loss of the porous material was measured at room temperature using a filter media tester. A filtering test using fly ash was carried out with a reverse air-cleaning at constant intervals. The developed material had a low pressure loss and a strength which could withstand use. Air-cleaning worked effectively through the aligned pores and almost 100% of the ash was trapped, maintaining low pressure loss.