MICROSTRUCTURE AND PROPERTIES IN POROUS SUPPORTS

In this work, we studied the dry pressing technique for making porous supports with average pore sizes about 1 mu m. Emphasis was placed on the microstructure characterization of pores, which included porosity, pore size and tortuosity. The relationship between these porous chara cteristics and other properties such as specific permeability and flex ural strength were also investigated. The tortuosity values, which wer e determined by a dynamic water expulsion method, were considered as r easonable indicators for pore connectivity and fell in the range of 2. 5 to 3.5 for our samples. The tortuosity would increase with increasin g forming pressure, which suggested that under a higher forming pressu re the particles would be packed more closely and therefore making the flow path more tortuous. Finally, our results seemed to indicate that the three porous characteristics, i.e., porosity, pore size and tortu osity, for samples made by the same fabrication technique might very w ell be correlated in certain relationships.