Surface segregation effect for prevention of oxidation in Ni-X (X=Sn, Sb) alloy by in situ photoelectron spectroscopy

Doi, Takashi*; Yoshigoe, Akitaka 

Ni-base alloys has been widely used for chemical plants because of their high strength and excellent oxidation resistance. In particular, the addition of Sn and Sb in Ni-base alloys significantly improves the metal dusting resistance. It is indicated that Sn and Sb are segregated on the alloy surface in the metal dusting environment; however, the details have not been clarified yet. The behavior of the Ni-Sn and Ni-Sb alloys under a high-temperature oxidation environment was investigated by in situ X-ray photoelectron spectroscopy. It was confirmed that Sn and Sb have been segregated at the surface of their alloys during oxidation in low oxygen potential environment. These results indicate that Sn and Sb segregation improves the metal dusting resistance.