Abstract
Porous Fe25Al–xSi intermetallics with various contents of Si were fabricated via reactive synthesis using Fe + Al + Si powder mixtures, in which the elemental Si was added to control the self-propagating High-temperature Synthesis (SHS) occurred during sintering process. The Si element added in Fe25Al could make the exothermic reactions in the synthesis process become mild and the total heat release from the system decrease. With increasing Si content from 0 to 5 wt-%, the open porosity, the maximum pore size and permeability increased from 38·14 to 50·12%, 27·9 to 35·7 μm and 5·13 × 10−12 m2 to 11·9 × 10−12 m2, respectively. Si element could affect the microstructure and phase evolution during the middle temperature sintering. Scattered τ1 ((AlSi)5Fe3) phase surrounded Fe2Al5 layer transformed into loop-shape with increasing Si content. Fe(Al1−x Si x )3 and Al3FeSi phases substitute Fe2Al5 phase as the main intermediary phase when the Si content is beyond 3 wt-%.