A facile route to produce Fe-Al intermetallic coatings by laser surface alloying

This work studies the feasibility of obtaining iron aluminide coatings on pure iron substrate by means of laser surface alloying (LSA). Pure Al was plasma spray coated on pure Fe substrate and subsequently laser alloyed by using multi mode continuous wave Nd-YAG laser at different output power and scanning rates. The aluminum content of the alloyed layer shows gradual change from surface to the inside of substrate. Detailed optical, SEM-EDX and XRD investigations were performed to characterize the phases formed during laser alloying. At 300 W laser output power, Al rich intermetallic phases mainly FeAl3, Fe2Al5 had formed with scanning rate in the range of 100-400 mm/min. However, at high power outputs (500 W) Fe-Al intermetallic phase had formed, which was found to have sound and crack free interface with the substrate.