Effect of segregated antimony on the oxidation of Fe–4%Sb single crystals

Antimony surface segregation and its effect on oxidation were investigated on (111) and (110) oriented surfaces of Fe–4%Sb single crystals by means of AES (Auger Electron Spectroscopy) and LEED (Low Energy Electron Diffraction). Oxidation experiments were performed at 300°C and 500°C using oxygen pressures between 1×10 −8 mbar and 5×10 −6 mbar for both sputter cleaned surfaces and antimony saturated surfaces. The presence of antimony on the surface retards or even prevents oxidation for both surface orientations and at both temperatures under investigation. LEED patterns show complex superstructures as a result of oxidation of clean surfaces, while for the antimony saturated surfaces, no additional reflexes were detected at a similar degree of oxidation. Different possibilities to interpret the role of antimony in oxidation are discussed.