Abstract
Surface roughness and surface oxides modify the thermal radiation properties of dark nonoxide compounds. Surface roughness results in the trapping of impinging light, thereby decreasing the specimen reflectance. At most, the observed differences in reflectance amount to about 10%. Surface oxide layers cause even larger changes, often amounting to 15% of reflectance. Thin oxide layers, of the order of 100 mμ, modify the thermal radiation properties in accordance with the properties of interference films. Thicker oxide layers, of the order of 1000 mμ, may also contribute their bulk thermal radiation characteristics. Heated nonoxide compounds are easily oxidized by trace amounts of oxygen present in inert atmosphere or high vacuum. It therefore becomes extremely difficult to completely eliminate surface oxidation during high-temperature emittance measurements.
© 1966 Optical Society of America
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Elihu A. Schatz
J. Opt. Soc. Am. 56(3) 389-394 (1966)
Roy F. Potter
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