Calorimetric Approach for Measuring Emittance and Normal Spectral Absorptance at Elevated Temperatures

摘要

A differential calorimeter designed to measure total hemispherical emittance and normal spectral absorptance as a function of temperature is described. The mathematical analysis necessary to calculate both of these parameters is presented. The experimental results obtained with a sample of SiC/A1203 (silicon carbide/alumina) are discussed. It was found that the emittance of SiC/A1203 is 1 at 200 deg C and decreases to about 0.81 at 700 deg C. The absorptance of CO2 CW laser radiation (10.6 micrometers) is 0.85 and remains constant within the range of 600 to 700 deg C.