An auger electron spectroscopic study of the corrosion behavior of an amorphous Zr40Cu60 alloy

The corrosion behavior of an amorphous Zr40Cu60 alloy in laboratory air (RH = 60 +/- 10%) at room temperature was studied by grazing incidence X-ray diffraction (GIXRD) and Auger electron spectroscopy (AES) combined with Ar ion sputter-etching In general, the corrosion behavior of the roll-side of the specimen which was in contact with the chilling roll during quenching was different from that of the freely solidified surface (top-side). The GIXRD data suggested that monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrO2) were formed under a surface layer of metallic copper which was also formed by corrosion of alloy. The t-ZrO2 was distributed more deeply than the m-ZrO2. By AES, it was clarified that a metallic copper layer covered with a very thin ZrO2 was placed in the topmost region, and that, under the copper layer on the roll-side surface, a sandwich structure of ZrO2 and metallic copper was formed, i.e. the corroded region consisted of several layers of ZrO2-rich and copper-rich layers distributed alternatively. On the top side, however, the oxidized layer did not develop significantly and the sandwiched structure of ZrO2 and metallic copper was not observed. Copyright (C) 1996 Elsevier Science Ltd