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-bas e 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 degreesC has three stages, including the initial, the stab le and the accelerative. Adding Ti into aluminisor quickened the oxidation and degradation of the coating, and made the oxidation stage advance from t he stable to the accelerative. The oxidation weight gains of coatings at lo wer temperatures of 900 and 1000 degreesC with theta -Al2O3 emerging were m ore than that at higher temperature of 1050 degreesC with only alpha -Al2O3 forming. (C) 2001 Elsevier Science Ltd. All rights reserved.