Suppression of the SHS reactions during synthesis of porous FeAl intermetallics by introducing silicon

Abstract A novel method for suppressing the Selfpropagating High-temperature Synthesis (SHS) reactions during synthesis of porous FeAl intermetallics by introducing silicon (Si) was proposed. The exothermic behaviors, microstructures and phase compositions of Fe/Al/Si compacts with a content of 1–5 wt% Si were investigated to gain an insight into the mechanism of Si for influencing the diffusion reactions in Fe-Al system. The results showed that the interdiffusion and reaction velocities of Fe/Al/Si compacts were restrained due to the segregation of Si in the Fe-Al interface, which could avoid the intensive heat release from Fe-Al reactions. After final sintering, diffusional homogenization of porous FeAl intermetallics could be achieved. The beneficial effect of Si in preventing SHS reactions has been further verified in the industrial manufacturing of FeAl filter elements.