High-temperature oxidation behavior of cold sprayed ZrC-modified NiAl bond coating

The NiAl, NiAl+0.5at%ZrC, NiAl+0.07at%ZrC coatings were prepared on the surface of IN738 superalloy by cold spraying of mechanically alloyed (ball-milled) NiAl alloy powders and a subsequent heat diffusion (protecting gas: Ar) process. The oxidation resistances of the resultant coatings were determined by isothermal oxidation at 1050 ℃ for 0.5 h, 1 h, 2 h, 4 h, 10 h, 50 h, 100 h and 200 h. The microstructure of the NiAl and NiAl+ZrC coatings after high-temperature oxidation were characterized by scanning electron microscopy and X-ray diffraction analysis. The results showed that oxidation kinetics of the NiAl+ZrC coatings coincided with parabolic law, and α-Al₂O₃ oxide scales were formed on the surface of both NiAl and NiAl+ZrC coatings during 1050 ℃ oxidation. The oxide growth rate on the NiAl+0.07%ZrC coating was lower than that of the NiAl+0.5%ZrC coating.