Advanced intermetallic iron aluminide coatings for high temperature applications

The limitations of traditional engineering materials like steels and nickel based alloys can be overcome with spray coatings of intermetallic iron aluminides, such as Fe3Al and FeAl, due to their unique ability to form alumina layer and protect base materials against high temperature corrosion. This review provides necessary background on the development of ductile iron aluminide alloys as engineering structural materials, as wear resistant materials and compares the high temperature oxidation and corrosion resistant properties with several high temperature steels. We then present the status on the Fe3Al and FeAl coatings and sheets obtained by various spray techniques such as atmospheric plasma spraying (APS), vacuum plasma spraying (VPS), high velocity oxy fuel spraying (HVOF) and cold spraying. The spray parameters, the microstructure, and the properties of the coatings are discussed and compared with the bulk properties of iron aluminide alloys. Finally, the paper discusses the application of spray techniques to obtain net shape three dimensional products with intelligent manufacturing techniques and achieve cost effective manufacturing by applying a layer of material as a coating instead of replacing the product obtained after melting, casting, and processing into desired shape.