Effect of Ru on the oxidation behavior of a fourth-generation single crystal superalloy at 900 °C

This paper investigates the influence of ruthenium (Ru) on the oxidation behavior of a fourth-generation nickel-based single crystal superalloy at 900 o C. By comparing oxidation kinetics curves, surface and cross-sectional oxidation products, and microstructures of alloys with and without Ru, it was found that the addition of Ru reduced the oxidation resistance of the alloy at 900 o C. Ru delays the formation of a continuous Al 2 O 3 layer, causing the initial oxidation stage to be dominated by a NiO layer, with the Al 2 O 3 layer becoming prominent only in the later stages. Additionally, the formation of volatile Ru-containing oxides does not significantly degrade the oxidation performance of the alloy, as this depends on the formation of the continuous Al 2 O 3 layer.