Properties of intermetallic Ni–Al coatings deposited by high-velocity air–fuel spraying

The formation of intermetallic Ni–Al coatings by high-velocity air–fuel (HVAF) spraying is considered. The energy states of particles are calculated to determine the optimum grain-size composition of NiAl and Ni 3 Al powders. The properties of HVAF coatings from commercial PN85Yu15 and PTYu5N powders and test NAS powder deposited on steel, copper, and aluminum substrates are analyzed. The phase composition and structure of the coatings are provided. The properties of the coatings (porosity less than 1.5%, adhesion with steel substrate 44–57 MPa) are as good as those of the coatings produced with other thermal-spraying methods. The microstructure of the coatings is mainly formed by solid particles and partially by fine molten particles.