Dual-wavelength reflectance-ratio (DWR) method applied to high-temperature metals

Applicability of the dual-wavelength reflectance-ratio (DWR) method to high-temperature spherical metals was investigated. Solid nickel, copper and platinum spheres were used as samples for establishing the experimental setup and procedure. The samples were heated inductively and their temperatures were monitored with a thermocouple attached to the sample. Their radiances were measured using a pyrometer at two different wavelengths, 900 and 1350 nm. Their temperatures were calculated by analyzing the sample radiances with and without reflection of an auxiliary light source. The obtained temperatures by the DWR method agreed with the temperatures measured by a thermocouple within 50 K in the temperature range from 850 to 1600 K.