Anomalous Behavior of the Internal Oxidation of Dilute Cu-Ni Alloys Under 1 atm. O_2 at 900 °C

摘要

The internal oxidation of Ni in dilute Cu-Ni alloys exposed to 1 atm. O_2 at 900 °C, and thus in the presence of external CuO_x scales, is absent for Ni levels below a critical value, extremely close to that required for the simultaneous equilibrium between the alloy and the oxides of the two components. For Ni contents not largely exceeding this limit the internal oxidation of Ni deviates from the classical behavior described by Wagner, approaching that predicted by Morral et al. for the precipitation of compounds with limited thermodynamic stability.