Ceramic filters must present not only high permeability and particle trapping efficiency, but also suitable mechanical strength. However, these parameters are influenced in different ways by the cellular structure. Large pores favor permeability, but lower removal efficiency of small particles. Small pores, on the other hand, enhance particle collection, although the filter pressure drop increases. The porosity is also essential for determining ceramic foam performance. Mechanical strength generally decreases with increasing porosity, even though permeability is improved. In this work, the relationship between mechanical strength and permeability has been investigated for 10 ppi (pores per linear inch) Al2O3-SiC filters. The amount of slurry impregnated on the organic struts walls during processing has been chosen as the control variable. The results have been compared with those obtained from cellular structures where the pore count variation ranged from 10 to 90 ppi.
ceramic filters; ceramic processing; mechanical strength; permeability
