HIGH TEMPERATURE SPECTRAL EMISSIVITY OF YTTRIUM, SAMARIUM, GADOLINIUM, ERBIUM AND LUTETIUM OXIDES

Spectral emissivities are given for Y/sub 2/O/sub 3/, Sm/sub 2/O/sub 3/, Gd/su b 2/O/sub 3/, Er/sub 2/O/sub 3/, and Lu/sub 2/O/sub 3/ in the visible portion of the spectrum for temperatures up to 1600 deg C. The data were obtained using a carbon arc image furnace as an energy source, a photovoltaic cell as a radiation detector, a thermocouple as a temperature detector, and a magnesium oxide smoked plate as a standard of reflectance. Emissivity was calculated from a curve of combined refiectance and emitted radiation versus temperature by using Kirchoff's law and a method of successive approximations to solve Wien's equation. (auth)