Spectralemissivity and optical properties at [formula omitted] for liquid uranium and zirconium at high temperatures

Abstract

The spectral emissivities, refractive indices, and extinction coefficients of pure liquid uranium and zirconium were measured versus temperature by He-Ne laser polarimetry at a wavelength of 632.8 nm. The experiments were conducted under containerless conditions using electromagnetic levitation and heating supplemented by CO 2 laser beam heating. Clean liquid metal surfaces were achieved by heating the specimens to high temperatures at which oxides evaporated and nitrides decomposed. Results were obtained for liquid uranium and zirconium in the temperature ranges 2000–2800 K and 2000–2600 K, respectively and included data for liquid zirconium undercooled by 125 K. The spectral emissivity of zirconium was equal to 0.345 and was independent of temperature. The spectral emissivity of uranium increased with temperature from 0.272 at 2000 K to 0.294 at 2800 K. The melting temperature of zirconium was determined from its emissivity and apparent melting temperature to be 2125±11 K , in good agreement with values in the literature.