Isothermal oxidation behavior of electrospark deposited MCrAlX-type coatings on a Ni-based superalloy

A MCrAlX-type coating has been prepared by electrospark deposition (ESD) and its isothermal oxidation behavior studied. The results indicate that deposition rate and surface roughness of the coatings increase with increasing spark pulse energy. A splattered porous morphology was observed in the surface layer, and underneath this, a uniform superfine columnar γ phase structure with a column width of about 0.6 μm. When exposed at 1000 °C, θ-Al2O3 formed rapidly in the early oxidation stage. After 100 h oxidation, a large amount of θ-Al2O3 was still present, and a dense and adherent, thin α-Al2O3 scale had formed beneath it.