The formation of Si-aluminide coating formed by plasma spraying and subsequent diffusion annealing on Ti-Al-7Nb intermetallic alloy

Purpose: In the article, the kinetic growth phenomena of aluminide coating formed by plasma spraying pure Al-Si powder and subsequent diffusion annealing on TiAl intermetallic alloy in inert atmosphere were investigated. Design/methodology/approach: The Al-Si powder was thermal sprayed (APS) on TiAl7Nb intermetallic alloy and annealed in Ar atmosphere during 5, 15, 30, 60, 240 and 480 min. The kinetic growth of the coating was observed using the scanning electron microscopy method (SEM), and chemical composition was analysed using the EDS method. Findings: The Kirkendall Effects pores formation, as well as titanium silicides on the grain boundary of TiAl3, was found. Research limitations/implications: The oxidation resistance of the developed coating might be analysed in further work. Practical implications: The developed coating might be used for the production of protective aluminide coatings on TiAl intermetallic alloys. Originality/value: The description of aluminide coating formation in a new technological process.