Effect of Material and Environmental Parameters on the Microstructure Evolution and Oxidation Behavior of a Ni-Based Superalloy Coated with a Pt-Modified Ni-Aluminide

The present work, performed on nickel aluminides deposited on a single Ni-based superalloy AM1, focuses on the effect of the following several parameters on the microstructural and chemical changes occurring during isothermal heat treatment at 1100°C for 50h : -oxygen pressure by comparing heat treatment under ambient air (PO2 = 0.2 bar) and under secondary vacuum (PO2 = 0.2x10-6 bar). -cooling rate after isothermal heat treatment by comparing furnace cooling (3°C/min) and water quenching (500°C/min). -Pt addition in the coating by comparing NiAl and NiPtAl coatings. Characterizations were performed using SEM, analytical TEM and electron microprobe analyses. The results show that these parameters have a strong influence on both the microstructural evolution and the oxidation of the thermal barrier coating (TBC) system. Appropriate heat treatments are essential to improve interfacial resistance and increase the durability of TBC systems.