Effect of sand blasting and glass matrix composite coating on oxidation resistance of a nickel-based superalloy at 1000 °C

The oxidation behavior of K38G superalloy, which is mechanically polished or sand blasted and then coated with glass matrix composite coatings, is investigated at 1000 °C. Results indicate that sand blasting pre-treatment enhances the resistance to oxidation and spallation of the glass coatings on superalloys by promoting formation of an alumina interlayer. The most important factors favoring formation of this alumina interlayer are discussed in terms of that sand blasting not only changes the microstructure of alloy, it also modifies the alloy composition at surface by affecting the progressing of interfacial reactions between the superalloy substrates and glass coatings.