Preparation and high temperature oxidation resistance of AlSiY coating by arc ion plating

Abstract

AlSiY coating with excellent antioxidant property was deposited using the arc ion plating technique on a nickel-base single crystal superalloy René N5. The microstructures and morphologies of the coatings, the elemental content and composition of the phases were analyzed by scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD). The results showed that the AlSiY coating was primarily comprised with β-NiAl phase with well combined with the substrate after heat treatment. The average oxidation rate of the coating for 300 h oxidation at 1050 ℃ was 0.8570 mg/cm2, superior to that of the substrate with 1.0035 mg/cm2. The coating exhibited good resistance oxidation during 1050 ℃, and the main phase was β-NiAl phase with high Al content after 300 h oxidation, which suggested that the coating could form a dense Al2O3 layer. In the 1100 ℃ oxidation process, although the depleted aluminum zone of γ′-Ni3Al was formed under the oxide layer after 300 h oxidation, the coating still had a high Al content, which could generate a continuous oxide layer on the surface of coating. The average oxidation rate of coating and substrate was 1.4070 mg/cm2, 3.2730 mg/cm2, respectively, which could provide good oxidation resistance for substrate. The investigation could provide some guidance for the preparation and industrial production of aluminide coatings.