Compositional Dependence of Normal Spectral Emissivity of Molten Cu-Fe Alloy

Normal spectral emissivity of molten Cu-Fe alloy with different compositions was measured at the wavelength of 807 nm using an electromagnetic levitator superimposed with a static magnetic field, which is capable of producing accurate normal spectral emissivity data because the applied static magnetic field suppresses translational and surface oscillations of a levitated sample to consequently reduce measurement uncertainties. Cu-Fe alloy samples used in this study were Cu97Fe3, Cu93Fe7, Cu92Fe8, Cu90Fe10, Cu80Fe20, and Cu70Fe30. The strength of the static magnetic field and temperature ranged from 3.0 to 3.5 T and 1350 to 1750 K, respectively. The measured normal spectral emissivity indicated negligible temperature dependence in a wide temperature range. In contrast, the compositional dependence indicated a distinct tendency in which the emissivity increased markedly with the composition of Fe up to 10 at pct.