Microstructural investigation of PGM-based alloy coatings for oxidation protection

It is well known that Pt addition significantly improves the resistance of aluminide coatings to high-temperature oxidation and hot corrosion, which has led to the widespread application of Pt modified aluminide coatings on the superalloy components of advanced gas turbine engines. Other platinum group metals (PGMs) such as Ir and Ru attract researchers for high temperature applications. In this study, oxidation properties of Pt-Ir and Pt-Ru based alloy coatings were investigated. Pt, Ru, and Ir were electroplated on a directionally solidified Ni-base superalloy DZ125. The cyclic oxidation test revealed that both Pt-Ir and Pt-Ru alloys exhibited good oxidation performance. The effect of substrate alloy and coating compositions on microstructural changes during cyclic oxidation tests were discussed.