The oxidation of some copper‐zinc alloys and a copper‐nickel alloy in pure oxygen at 700°C has been studied to determine the occurrence of a displacement reaction of the type as proposed by C. Wagner. The formation of BO in the displacement reaction has been shown to occur by observing a change in the oxide scale by metallographic examination and by noting a change in the rate of oxidation as given by the parabolic reaction rate constant. A change in the oxidation rate for several samples was further emphasized by observing the rates during two periods of oxidation which were separated by an isothermal annealing period in an inert gas.