The Spectral Emissivity of Color Metals in Pure and Oxidized States

In the present paper, the values of the spectral emissivity of color metals i.e. gold and copper, and copper heated in oxidizing atmospheres are measured at the temperature of 1000°C, just below their melting points, and within the wavelength region from 0.38 to 0.94 μm. Also the values of the spectral reflectance of gold and copper are measured at room temperature. And the spectral emissivity calculated from this spectral reflectance. Then, experimental results are analyzed by the dispersion formula concerning the free electrons and bound electrons. Thus, the formula can be applied whether wavelength dependency of the spectral emissivity is negative and variable (gold and copper), or positive and nearly constant in the case of copper heated in oxidizing atmosphere.