A Database of Normal Spectral Emissivities of Metals at High Temperatures

Abstract

The normal spectral emissivity and its time variation were measured systematically for a total of thirty kinds of pure metals and alloys at temperatures between 780 and 1200°C. The spectral data were obtained at about 100 wavelengths from 0.55 to 5.3 μm under different environmental conditions including oxidation. The spectral data were stored in a database with supplementary information on the specimens. Clear oscillations of the spectral emissivity with time and wavelength were observed for nickel, Inconel, and SUS444 as surface oxidation progressed, while emissivity variations were rather monotonic for other metals such as titanium, cold-rolled steel, and SUS310S. The surface roughness was measured for all specimens by a contact-type instrument before the measurements, and recorded as supplementary information in the database. The database was built on a personal computer operating system (Windows95) to facilitate the dissemination to researchers and engineers interested in the emissivity of metals. Indexes to the emissivity data are metal name, wavelength, temperature, time, and degree of oxidation represented by an effective thickness of oxide film on the specimen surface.