A Novel Method for In-Situ Synthesis of FeAl Dense Coating Deposited by Very Low Pressure Reactive Plasma Spraying

With the purpose of the fabrication of high-quality FeAl coating, a so-called very low pressure reactive plasma spraying (VLP-RPS) technique that combine VLPPS and SHS processes was realized in the present study. A dense and homogeneous FeAl coating was successfully in situ synthesized by reactive plasma spraying of Al/Fe₂O₃ composite powder under an atmospheric pressure of 1 mbar. The phase composition and microstructural features of the coating were characterized by XRD and SEM. The results indicated that B2 ordered FeAl phase was synthesized, and the coating featured a super-dense and defect-free microstructure. The formation mechanism of the coating was elucidated. The fracture mechanism of the coating could be principally contributed to a brittle failure, and the appearance of some dimples in the local zone corresponded to a tough fracture characteristic. In addition, the microhardness of the coating was also measured.