Abstract
Intermetallic materials have excellent high temperature oxidation resistance and erosion, cavitation resistances and are promising coating materials with many potential industrial applications. In this study, the formation of Fe-Al intermetallic compound-based coating was performed by cold spraying assisted by a post-annealing treatment. Fe-Al alloy composite powder containing 20wt% WC-Co was produced by ball milling process. Nano-structured Fe-Al alloy coating was deposited through cold spraying. The coating was annealed at different temperatures. The microstructure of the coating was characterized by scanning electron microscopy, optical microscopy and x-ray diffraction analysis. It was found that the microstructure of the as-sprayed coating depended significantly on the microstructure of the powder. A Fe-Al intermetallic phase was formed during the annealing at a temperature higher than 500°C. Moreover, grain growth occurred with the increase of the annealing temperature. The results showed that the microhardness of the as-sprayed coating reached 600HV and more. The effect of the annealing treatment on the coating microstructure and hardness was examined.
