High temperature oxidation behavior of magnetron sputtered NiCrAlY coatings on PCrNi3MoVA steel

Specimens with NiCrAlY coatings, prepared by magnetron sputtering, were deposited on PCrNi3MoVA steel substrate. The specimens were isothermally oxidized at 850°C for 100 h in air. Oxidation behavior of the coatings was analyzed by means of XRD, SEM and EDAX analysis. The results show that the NiCrAlY coatings substantially increase the high-temperature oxidation resistance of PCrNi3MoVA steel and the Al2O3 oxide layer with good adhesion can form on the sputtered NiCrAlY coatings, and the NiCr2O4 and Fe2O3 oxide layers form at the bigger gaps between columnar grains. At the same time, the obvious interdiffusion occurs between element Fe in the substrate and element Ni in the sputtered NiCrAlY coatings, while element Cr mainly distributes at the interface and element Al mainly distributes on the surface and at the interface where Al reacts with O to form Al2O3.