THE CHEMICAL-STATES OF PHOSPHORUS ON THE IRON SURFACE

The main purpose of this study was to investigate the segregation and oxidation of phosphorus on the polycrystalline iron surface using the AES and XPS methods. The segregation of phosphorus begins at 600 K and the maximum concentration of phosphorus on the surface is achieved at 720 K, as in the case of a monocrystalline sample. The segregation of sulphur begins above 720 K, whereas the phosphorus surface concentrat ion decreases. The oxidation of the iron surface covered with phosphor us results in the formation of both the oxygen-phosphorus bonds and th e oxygen-iron bonds. The different forms of surface species have been proposed.