Total hemispherical emissivities of copper, aluminum, and silver.

The temperature variation of the total hemispherical emissivities of Cu, Al, and Ag has been studied by using a temperature decay method in the 150-1000-K range. The results obtained are found to support, for the first time, a classical relaxation theory developed by Parker and Abbott. The experimental emissivity data are used to calculate the emissive relaxation times tau for Cu, Al, and Ag at various temperatures in this range. These tau values are found to be practically insensitive to temperature, a behavior contrary to that shown by the electrical relaxation times calculated from the resistivity vs temperature data of these metals.