High-temperature oxidation of Cu-10 wt% Ni and Cu-15 wt% Ni at 900–1050°C

Copper with 10 and 15 wt% Ni has been oxidised in the temperature range 900–1050°C and in oxygen pressures from 5×10−4 to 1 atm. The oxidation kinetics are essentially parabolic and the oxide scales are composed of mainly two regions; an outer relatively dense layer of copper oxide and an inner layer comprising Cu2O, NiO-particles and porosity. The outer region grows by outward diffusion of copper whereas the inner layer grows by outward copper diffusion and inward dissociative transport of gaseous oxygen. The oxygen pressure dependence, the amount of porosity and the relative thickness of the inner region depend on the reaction conditions and the nickel content. These dependencies have been interpreted to reflect different rates of plastic deformation in the inner region of the oxide.