High-temperature oxidation of FGH96 P/M superalloy

High temperature oxidation behaviors of FGH96 P/M superalloy have been studied in air at temperatures ranging from 600 to 1000°C. By means of isothermal oxidation testing. X-ray diffraction, SEM (scanning electron microscopy), and EDS (energy dispersive X-ray spectroscopy) analyses, the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased, the oxidation rate, the scale thickness, and scale spallation increased. FGH96 P/M superalloy exhibits good oxidation resistance at temperature below 800°C. The oxidation kinetics follows an approximately parabolic rate law, and the oxide layer was mainly composed of Cr2O3, TiO2, and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium, titanium, and oxygen through the oxide scale.