Porous Fe-Sialloys with different nominalcompositions ranging from Fe-10wt% Sito Fe-50wt% Siwere fabricated through a reactive synthesis of Fe and Sielementalpowder mixtures.The effects of Sicontents on the pore structure of porous Fe-Sialloy were investigated in detail.The results showed that the open porosity,gas permeability and maximum pore size of the porous Fe-Sialloys increased with increasing Sicontents,indicating that the porosity and pore size can be tailored by changing the Sicontents.The pore structure parameter including the open porosity,gas permeability,maximum pore size obeyed the HagenPoiseuille formula with the constant G=0.035 m^（-1_Pa^（-1）s^（-1） for the reactively synthesized porous Fe-Sialloys.The mechanicalproperty of the porous Fe-Sialloys showed applicability in the filtration industries.
The tortuosity factor is the most critical parameter for the pore characteristic of porous materials. The tortuosity factor for porous FeAl intermetallics was studied based on the Darcy law and Hagen-Poiseuille equation. Porous stainless steel with the same pore structure parameter as porous FeAl was fabricated by powder metallurgy method for comparison. The results show that the tortuosity factor of porous FeAl intermetallics is smaller than that of porous stainless steel when their pore structure parameters are the same. The average tortuosity factor is 2.26 for the porous FeAl material and 2.92 for the porous stainless steel, calculated by Hagen-Poiseuille equation. The reason of the different tortuosity factors for porous FeAl and porous stainless steel was also explored through studying the pore formation mechanisms of the two types of porous materials.
