Hot-Dip Aluminizing of Low Carbon Steel Using Al-7Si-2Cu Alloy Baths (original) (raw)

Hot-dip aluminizing of low carbon steel was done in molten Al-7Si-2Cu bath at 690°C for dipping time ranging from 300 to 2400 seconds. Characterization of the intermetallics layer was done by using scanning electron microscope with energy dispersive spectroscopy. Four intermetallic phases,τ5-Al7Fe2Si,θ-FeAl3,η-Fe2Al5, andτ1-Al2Fe3Si3, were identified in the reaction layer.τ5- Al7Fe2Si phase was observed adjacent to aluminum-silicon topcoat,θ-FeAl3betweenτ5andη-Fe2Al5,η-Fe2Al5adjacent to base material, andτ1-Al2Fe3Si3precipitates within Fe2Al5layer. The average thickness of Fe2Al5layer increased linearly with square root of dipping time, while for the rest of the layers such relationship was not observed. The tongue-like morphology of Fe2Al5layer was more pronounced at higher dipping time. Overall intermetallic layer thickness was following parabolic relationship with dipping time.