High-temperature oxidation of Cu–Al–Ni–Mn shape-memory alloy

Abstract

The isothermal oxidation behavior of the Cu-11.35Al-3.2Ni-3.5Mn (wt.%) shape-memory alloy (SMA) in the temperature range of 500–900°C in oxygen was studied using the thermogravimetric (TG) method. TG curve showed that the alloy has parabolic isothermal oxidation characteristics. The effect of oxidation on the surface morphology and chemical composition of the Cu–Al–Ni–Mn alloy was determined by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The oxidation rate of SMA increases up to 700°C, remains stable at 800°C, and increases again up to 900°C. The XPS analysis identified that the corrosion products mainly contained MnO₂, MnO/Mn₂O₃, and Al₂O₃.