Iron aluminide coatings on ferritic steels by CVD-FBR modified process with Hf

This work studies the feasibility of obtaining iron aluminide coatings on ferritic–martensitic steels by means of Chemical Vapour Deposition in fluidized bed reactor (CVD-FBR), adding small amounts of Hf powders in the bed that causes an increase in the deposition rate, since the atmosphere of reaction is modified. Thermodynamic calculations were performed before the experimental study to investigate possible changes in the CVD atmosphere of deposition in the Al/Hf deposition system in comparison to the single aluminization. The coatings are formed of Al-rich iron aluminides, growth mechanism of which is by reaction–diffusion processes. The preliminary results are discussed in this work.