High-temperature oxidation behavior of aluminide coatings on a new cobalt-base superalloy in air

The high temperature oxidation behavior of aluminide coatings on the Co-base superalloy DZ40M by low-pressure vapor deposition has been investigated. The results showed that the isothermal oxidation process of the coatings in air at 900–1100°C has three stages, including the initial, the stable and the accelerative. Adding Ti into aluminisor quickened the oxidation and degradation of the coating, and made the oxidation stage advance from the stable to the accelerative. The oxidation weight gains of coatings at lower temperatures of 900 and 1000°C with θ-Al 2O 3 emerging were more than that at higher temperature of 1050°C with only α-Al 2O 3 forming.