Accession Number : AD0436887


Title :   TOTAL NORMAL AND TOTAL HEMISPHERICAL EMITTANCE OF POLISHED METALS. PART 3


Descriptive Note : Rept. for 27 Feb-19 Dec 1962


Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA


Personal Author(s) : Abbott, G L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/436887.pdf


Report Date : Dec 1963


Pagination or Media Count : 41


Abstract : The total hemispherical emittance, the total normal emittance, and the variation of electrical resistivity with temperature were measured on aged surfaces of tantalum, niobium, and tungsten in a vacuum over a temperature range from 1000 K to 3000 K (subject to the material). In addition, the normal spectral emittance at 0.65 micron was measured on tantalum and niobium. The total hemispherical emittance was obtained from the measured power dissipation within the uniform temperature region at the center of an electrically heated ribbon; its temperature being measured with a thermocouple or an optical pyrometer when the spectral emittance was known. The total normal emittance was determined by using a radiation thermopile. The ratio of total hemispherical to total normal emittance was also calculated directly from the angular distribution of radiation obtained by revolving the ribbon within the field of view of the thermopile. Some data are also included on molybdenum from a previous report.


Descriptors :   *ELECTRICAL RESISTANCE , *HIGH TEMPERATURE , *TANTALUM , *TUNGSTEN , EMISSIVITY , INSTRUMENTATION , MEASUREMENT , MOLYBDENUM , NIOBIUM , PLATINUM , REFRACTORY METALS , SCIENTIFIC RESEARCH , SURFACES , TEMPERATURE , THERMAL RADIATION , THERMOCOUPLES


Subject Categories : Metallurgy and Metallography
      Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE