Oxidation resistant aluminized MCrAlY coating prepared by spark plasma sintering (SPS)

The oxidation resistant aluminized NiCoCrAlYTa single and multi layered coatings were prepared on a nickel base superalloy substrate by Spark Plasma Sintering (SPS) process to improve high temperature corrosion and oxidation behavior of materials with different compositions. The 8 mm diameter disk substrate with mechanically polished surface of .25 μm diamond grit was prepared from a single crystal nickel-base superalloy. The SPS prepared layered coatings show a homogeneous microstructure with no porosity and a good adherence in the substrate. The layered coatings are found to be composed of three phases such as gamma, gamma prime, and beta. The interface between superalloy and coating shows an interdiffusion layer of 2 μm thick, and segregation of tantalum carbide TaC phase is observed at the outer side of the diffusion layer.