High-Temperature Oxidation Behavior of Cold-Sprayed MCrAlY Coatings

Abstract

Cold spray is a new technique that can be used instead of the conventional thermal spray technique to provide a dense and low-oxide-content metallic coating. Conventional thermal-sprayed MCrAlY coatings are widely used for land-based gas turbine applications against high-temperature oxidation and hot corrosion. Recently, thick MCrAlY coatings were successfully obtained with cold spray process. The cold-sprayed MCrAlY coatings are denser than the low-pressure plasma-sprayed MCrAlY coatings. In order to evaluate the high-temperature oxidation behavior of cold-sprayed MCrAlY coatings, high-temperature exposure tests of cold-sprayed and low-pressure plasma-sprayed MCrAlY coatings were performed. Moreover hardness-changing behavior within high temperature exposure tests were investigated. From the results of exposure tests in an atmospheric environment of 1100°C, it can be observed that the cold-sprayed MCrAlY coatings have a lower oxidation ratio than that of the low-pressure plasma-sprayed coatings in this environment since the cold-sprayed coatings are denser than the low-pressure plasma-sprayed coatings. Moreover, cold-sprayed MCrAlY coatings have similar hardness changing tendency as low-pressure plasma-sprayed MCrAlY coatings. Therefore, the cold-sprayed MCrAlY coatings may have possibility to apply the gas turbine applications.