Elemental evaporation and its effect on pore structure in porous Fe-Al alloys' vacuum sintering

Porous Fe-Al alloy has been prepared by powder metallurgy through partial diffusion and reactive synthesis using Fe, Al mixture powder as raw materials. The mass and final pore structure changes of porous Fe-Al were characterized by the XRD, SEM, EDS, etc. The results show that the mass loss rate is 0.05% at the final sintering temperature of 1000°C, while it is 10.53% at 1300°C both holding for 4 h. The pore size, open porosity and permeability of porous Fe-Al increase with the increasing of sintering temperature and the elemental evaporation is stronger along with surfaces of pore walls. Based on the MIEDEMA model and LANGMUIR equation, the reason for elemental evaporation during vacuum sintering was analyzed through calculation. The main reason for the mass loss of porous Fe-Al is that Al evaporates intensely during sintering, which leads to the mass and pore structure changes of porous Fe-Al.