Factors Influencing Thermal Radiative Properties of Metals

0434010 - ÚPT 2015 RIV CZ eng C - Konferenční příspěvek (zahraniční konf.)
Králík, Tomáš - Hanzelka, Pavel - Musilová, Věra - Srnka, Aleš
Factors Influencing Thermal Radiative Properties of Metals.
Cryogenics 2014. The 13th IIR International Conference Proceedings. Praha: Icaris, 2014, s. 239-247. ISBN 978-2-36215-002-9. ISSN 0151-1637.
[Cryogenics 2014. The IIR International Conference /13./. Praha (CZ), 07.04.2014-11.04.2014]
Grant CEP: GA MŠMT(CZ) LO1212; GA MŠMT ED0017/01/01; GA ČR(CZ) GA14-07397S
Institucionální podpora: RVO:68081731
Klíčová slova: emissivity * absorptivity * radiative heat transfer * surface finish * cryogenics
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus

Data on thermal absorptivity and emissivity are important for calculations of heat flows in cryogenic devices. Although thermal radiative properties of materials used in cryogenics are measured, published and used for more than sixty years we have noticed that sometimes users of that data don’t well understand the significance of individual factors influencing thermal radiative properties. The sensitivity of the thermal radiative properties of metals to the condition of the surface and the difficulty of measurement, especially at low temperatures is probably the reason of dispersion of the published values. The effect of the material and its purity, finishing (machining, mechanical or chemical polishing) and of the protective coatings or accidental layers (water, oxidation) on the thermal radiative properties is not always obvious. Influence of the material, surface treatment, roughness and layers on the surface is discussed on the basis of our 20 year experience with measurement of the emissivity and absorptivity in the range from 20 K to 300 K.
Trvalý link: http://hdl.handle.net/11104/0238158