Emissivity measurements on some metals and oxides using multiwavelength spectral radiometry

摘要

The emissivities of tungsten (W), platinum (Pt), iron (Fe), corundum (Al sub 2 O sub 3 ), zirconia (ZrO sub 2 ), and sodium metasilicate (Na sub 2 SiO sub 3 ) have been measured by a new approach. The metals platinum and tungsten were heated electrically to the melting temperature and the power was calibrated against the temperature by visual observation of the melting and in-situ x-ray measurements of the lattice parameters. Radiation spectrometry was then used to obtain the thermal emission spectra at known temperatures. The spectral data were fitted with Planck's function to obtain emissivity and its dependence on temperature and wavelength. The emissivity data at 0.8 mu m wavelength for measured solids at melting temperatures are: W, 0.34; Pt, 0.44; Fe, 0.28; Al sub 2 O sub 3 , 0.40; ZrO sub 2 , 0.29; Na sub 2 SiO sub 3 , 0.21. Pion Limited, London.