Evolution of oxide layer during high-temperature oxidation of NiCoCrAlY coating via laser cladding on 304 stainless steel

In this study, the evolution of an oxide layer with time at 950 °C for NiCoCrAlY coating via laser processing on 304 stainless steel was investigated. The results showed that the NiCoCrAlY coating had a lower oxidation rate and a smaller oxidation weight gain in the whole oxidation process. A Cr2O3 film was formed on the surface of the coating, and Al2O3 appeared in the internal oxidation zone. With an increase in the oxidation time, the Cr2O3 layer gradually lost its protective effect, the spinel increased, and the internal oxidation zone gradually increased. Finally, Al2O3 controlled the subsequent oxidation behavior.