Abstract: In situ XPS was used to study the anti-oxidation behavior of Co and B in nano-sized Ni-Co-B amorphous alloy and the relationship between the surface contents and the treating oxidation conditions by O₂ as well as the changes of the surface elemental contents with the depth of the sample. It was found that the elemental B was preferably oxidized, then the elemental Co could be oxidized. After all elemental B and Co were used up, the surface elemental Ni began to be oxidized by O₂. In addition, the oxides from B and Co were inclined to enrich on the surface after the oxidation. It was the preferential oxidation of B and Co that protected the Ni active centers from oxidation during the catalytic hydrogenation.

Key words: Amorphous Ni-Co-B alloy, Anti-oxidation behavior, In situ XPS