Oxidation characteristics of a MnCuNiFe damping alloy

The oxidation behavior of manganese-copper alloys in air was investigated at different temperature by using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction. The mass gain of the oxide scale conforms to the parabolic law, and exhibits an abnormal increase at 1000 °C. The scales formed are composed of two different layers, and a small amount of (FeO) 0.099 (MnO) 0.901 is detected throughout the whole scale. The inner layer contains MnO with a preferential orientation of a (200) crystal plane, while a mixture of MnO and Mn 3 O 4 presents in the outer layer. It is found that Cu and Ni enrich at the matrix adjacent to the oxide scale in which their corresponding oxides are not observed. The mechanism behind the phenomenon is elucidated according to the oxidation thermodynamics, and then surface peeling process after heating is recommended from the viewpoint of safety production.