EFFECT OF ELECTRON-DENSITY TRANSFER BETWEEN COMPONENTS ON THE PHYSICOCHEMICAL PROPERTIES OF THE FE-CR-SI ALLOYS

The mechanism of the effect of alloying elements on the physicochemica l properties of alloys was considered for the Fe-Cr-Si system as an ex ample. It was shown by Mossbauer spectroscopy that silicon is an elect ron density acceptor in Fe-Cr alloys. The particular role of orbital e lectronegativity, which serves as a measure of donor-acceptor interact ions between the alloy components, is stressed. On the other hand, XPS data imply that silicon in the passive film acts as a donor of electr on density toward iron and chromium. The effect of the donor-acceptor properties of silicon in alloy and in oxide changes the energetic char acteristics of their interaction with water and chloride ions. From th is viewpoint, an explanation is given for some features of the corrosi on-electrochemical behavior of X25 ferritic steel when it is alloyed w ith silicon.