Oxidation of copper at high temperatures

Abstract

The kinetics and mechanism of copper oxidation have been measured over the temperature range 900–1050°C and the pressure range 5×10⁻³ to 8×10⁻¹ atm. It has been shown that, at the pressures lower than the dissociation pressure of CuO, the oxide scale formed on flat fragments of the copper specimens is compact and composed of a single layer, adhering closely to the metallic base. Growth of the scale proceeds under these conditions by outward diffusion of metal. The rate of the process under the conditions for which single-phase scales are formed increases with increasing oxygen pressure according to the equation:

$${\text{k''}}_{\text{p}}^{} = const {\text{p}}_{{\text{O}}_{\text{2}} }^{{\text{1/3}}{\text{.9}}} $$

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the activation energy for oxidation is 24 ± 2 kcal/mole. On the basis of theFueki-Wagner method and the method proposed in the present work, the self-diffusioncoefficients of copper in cuprous oxide were calculated as a functionof oxygen pressure and temperature. It has been shown that distribution of thedefect concentration in the growing layer of the scale is linear.