In this work, iron aluminide coatings were developed by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic-martensitic steels. Small additions of zirconium powder were introduced in the fluidized bed; as a consequence, the obtained coatings are thicker than that without zirconium additions. When Zr powders are added in the fluidized bed, the deposition atmosphere drastically changes, leading to increase the deposition rate. Thermodynamic calculations were carried out to simulate the modifications in the CVD atmosphere in the Al/Zr deposition system in comparison to the single aluminization. In order to optimize the conditions of the deposition, parameters such as temperature and concentration of zirconium introduced into the bed were evaluated and compared with the results obtained for the single aluminum deposition.