Preliminary Results of the Isothermal Oxidation Study of Pt-Al-NiCoCrAlYTa Multi-Layered Coatings Prepared by Sparks Plasma Sintering (SPS)

MCrAlY coatings (where M = Co, Ni or Co/Ni) are widely used on turbine blades and vanes as oxidation and corrosion resistant overlays or as a bond-coating in thermal barrier coatings systems. MCrAlY are usually fabricated by Plasma Spraying, Physical Vapour Deposition, High Velocity Oxy-Fuel spraying or electrolytic techniques. The use of emergent Spark Plasma Sintering technique as a preparation method for NiCoCrAlYTa coatings has been presented previously [1]. SPS technique allows fast development of new coatings with a one-step fabrication of multilayered coatings. This work presents first results of the long term isothermal oxidation behaviour of Pt-Ni aluminide/NiCoCrAlYTa multi layered coatings. The obtained coating is dense and homogeneous. Isothermal oxidation up to 500 h at 1100°C leads to the formation of an adherent alumina scale with Y-rich precipitates and deep intergranular oxidation.