Flame spraying of Al/Fe3Al-Fe3AlCx composites powders obtained by vertical ball milling

Aluminum composite coatings deposited by flame spray with nanometric materials as reinforcement have been used to produce high-performance coatings. The addition of carbon to Fe3Al, forming carbides Fe3AlCx (phase κ), enhances the properties of Fe3Al and contributes toward the increase in the microhardness of the coating, thus justifying the use of intermetallic as reinforcement to the Al coating. This study aims to obtain mechanically cladded Al (micro)/Fe3Al-k (nano) powder by a vertical ball mill (VBM) with two different compositions of reinforcement (20% and 40%) for producing powder flame spray coatings. The effect of the VBM powder processing route on phase formation, powder morphology, and coating microhardness was evaluated. The characteristics of the powders were investigated through their being subjected to milling times of 5, 10, 15, 20, and 30 min in VBM. The processing time of 15 min was the most suitable for obtaining Al composites with 20% and 40% Fe3Al-κ with no significant changes in particle size, no solid-state reactions, and Al particles cladded with Fe3Al–κ. Deposits of Al/Fe3Al-κ composite by flame spray were reached without separating the Fe3Al-κ nanoparticle from the Al microparticle during flight while forming composite coatings with aluminides particles dispersed throughout the coating. The coating formed presented up to 600 μm of thickness and microhardness of 197 ± 47Hv for 20% and 158 ± 49Hv for 40%.