Infrared emittance of Cux–Ni1−x alloys

The aim of this work was to study Cu–Ni alloys and establish a relation between alloy concentration and infrared emittance for wavelengths of the order 10 µm, which is of interest in room temperature applications. The resistivity was measured at room temperature for the same alloy compositions as the emittance in order to investigate the validity of the Hagen–Rubens relation in the infrared wavelength range for Cu–Ni. The Hagen–Rubens relation is verified for both the copper-rich and nickel-rich samples. We therefore assume strong electron scattering from impurities so that intraband transitions dominate over interband transitions in the infrared wavelength range. The validity of the Hagen–Rubens relation can, as a good approximation, also be used for the integrated thermal emittance.