Oxidation and Hot Corrosion Performance of NiCoCrAlY Coatings Fabricated Via Electrolytic Codeposition

The oxidation and hot corrosion performance of NiCoCrAlY coatings fabricated via electrolytic codeposition was investigated. The cyclic oxidation behavior of NiCoCrAlY coatings on Ni-based superalloys was evaluated at 1000 and 1100 °C. Preliminary Type I hot corrosion testing was conducted to assess the hot corrosion resistance of these coatings in a Dean rig with flowing O 2 + 0.1% SO 2 gas. NiAl coatings synthesized by a non-contact pack cementation method were included in the oxidation and corrosion tests for comparison. The NiAl coatings exhibited excellent oxidation resistance; however, they showed very poor hot corrosion performance at 900 °C. The electro-codeposited NiCoCrAlY coatings demonstrated good overall resistance to both cyclic oxidation and hot corrosion and also showed better chemical/microstructural compatibility with the superalloy substrates.