Structure and properties of aluminized coatings on nickel and nickel alloys

1. Aluminizing prevents oxidation for a long time (over 6000 h) in heat-resisting nickel alloys with intermetallic hardening phases of the Ni3Al type at temperatures below the temperature of the solution of the hardening phase in the solid solution. 2. The protective properties of the coating are determined by the presence on the surface of a thin oxide film α-Al2O3 formed in the oxidation of intermetallic phases, but during use the Ni2Al3 and NiAl phases in the aluminized coating are gradually transformed into Ni3Al, which is in thermodynamic equilibrium with the phases composing the alloy.