Cold spraying of Fe/Al powder mixture: Coating characteristics and influence of heat treatment on the phase structure

In this paper, an iron/aluminum composite coating was deposited by cold spraying using iron and aluminum powder mixtures. The coating was annealed at different temperatures to aim at forming an iron aluminide intermetallic based coating. The results showed that a thick dense Fe/Al composite coating with uniformly distributed Fe and Al particles can be deposited by cold spraying. The compositions of the as-sprayed Fe/Al coating were nearly the same as that of the initial Fe/Al powder mixture. The intensive deformation of particle on impact caused elongation of the grain and disrupted the thin oxide films on powder surface. After annealing at a temperature of 600 °C, an intermediate phase Al5Fe2 coexisted in the deposit with remaining Fe and Al. With increasing annealing temperature to 900 °C, the deposit transformed to mainly FeAl phase with a trace of remaining Fe phase.