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 Diffractio n). Oxidation experiments were performed at 300 degrees C and 500 degrees C using oxygen pressures between I X 10(-8) mbar and 5 X 10(-6) mbar for bot h sputter cleaned surfaces and antimony saturated surfaces. The presence of antimony on the surface retards or even prevents oxidation for both surfac e orientations and at both temperatures under investigation. LEED patterns show complex superstructures as a result of oxidation of clean surfaces, wh ile for the antimony saturated surfaces, no additional reflexes were detect ed at a similar degree of oxidation. Different possibilities to interpret t he role of antimony in oxidation are discussed. (C) 1999 Elsevier Science B .V. All rights reserved.