Influence of substrate composition on the oxidation performance of nickel aluminide coating prepared by pack cementation

• The substrate composition significantly affects the oxidation of NiAl coating.
• DZ125 and DD6 coating systems exhibit better spallation resistance due to Hf.
• TiO2 and Ti-rich oxide are responsible for the oxide spallation of DZ411coating.
• The interface rumpling also leads to the oxide spallation of DZ411coating.
• The interface voids result in the oxide spallation of the Hastelloy X coating.

Effects of substrate compositions on the microstructure and oxidation behavior of NiAl coating by pack cementation were investigated. It is found that substrate compositions have a profound influence on the coating microstructure and oxidation performance. The DZ125 and DD6 coating systems exhibit better spallation resistance due to the presence of Hf. The interface rumpling, as well as the TiO2 and Ti-rich oxide are responsible for the oxide spallation of the DZ411 coating system. The voids at the oxide/coating interface, leading to a lower interfacial adhesion, result in the worst oxide spallation of the Ni and Hastelloy X coating systems.