High-temperature oxidation behavior of Inconel 625 superalloy manufactured by wire arc additive manufacturing (WAAM) technique was investigated. Results showed that microstructure of the as-built alloy contained Ni-based solid-solution dendrites along with MC carbide, Laves, and δ phases. Holding of samples at 800–1000 °C for 20 h resulted in the formation of Cr₂O₃ and Ni₃Nb phases on the surface of the alloy. However, at 1100 °C, oxidation of Ni₃Nb led to the formation of CrNbO₄ at the oxide/alloy interface. The growth kinetics of the oxide layer followed a parabolic law, and the

diffusion activation energy was calculated as 167 kJ/mol.