Effect of cerium addition on oxidation behavior of 25Cr20Ni alloy under low oxygen partial pressure

The influence of Ce addition on the oxidation behavior of 25Cr20Ni alloy at 950 °C under low oxygen partial pressure was investigated. The oxidized samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and scratch tester to obtain the oxide phases, morphology, thickness, composition and adhesion property of the oxide scales. The experiment results indicated that a small amount of Ce addition (0.02 wt.% or 0.05 wt.%) promoted oxidation resistance and inhibited the growth of the needlelike oxide. The Ce addition also decreased the formation of MnCr2O4 but promoted the SiO2 formation underneath the Cr2O3, which largely contributed to the improvement of oxide scale spallation resistance. For the sample with 0.3 wt.% Ce addition, the oxidation rate significantly increased and the spallation resistance of the oxide scale decreased.