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Spectral Emissivities of Graphite and Carbon

1953; American Institute of Physics; Volume: 24; Issue: 5 Linguagem: Inglês

10.1063/1.1721341

1520-8850

R.J. Thorn, O. C. Simpson,

Thermography and Photoacoustic Techniques

The spectral emissivities of graphite and carbon have been determined at a wavelength of 0.653μ in the temperature range of 1285 to 2035°K and have been found to be temperature dependent in accordance with a prediction from a relation between reflectivity and resistivity. For polished graphite of high purity having a resistivity of about 1120 microhm-cm the value obtained is 0.78; the value obtained for a polished high density graphite having a resistivity of 1740 microhm-cm is 0.78; and that for polished spectroscopic carbon having a resistivity of 5080 microhm-cm is 0.79. If graphite is sublimed from a polished surface, the latter becomes roughened, so that the emissivity increases. In one particular experiment it attained a value of 0.90.