Oxidation-Resistant Coatings for TiAl Intermetallics—Short Review

This article presents a review of current trends in the development of protective coatings for TiAl alloys. These materials have been indicated as potential replacements for nickel-based alloys for several decades; however, many problems related to their application have not yet been solved, such as low resistance to oxidation and high-temperature corrosion, limited wear and erosion resistance, as well as susceptibility to microstructural changes under demanding conditions. Research in this area has been conducted for many years; nevertheless, new concepts and types of coatings are constantly being developed, particularly for third- and fourth-generation TiAl alloys. This article presents a review and classification of protective coatings used for TiAl alloys, with particular emphasis on research results published in the scientific literature of the last decade. In addition to a literature review concerning coating types and applied technologies, new trends and concepts in this field proposed by the co-authors will also be presented.