MEASUREMENTS OF TOTAL HEMISPHERICAL EMISSIVITY OF SEVERAL STABLY OXIDIZED METALS AND SOME REFRACTORY OXIDE COATINGS
A description of the apparatus and methods used for obtaining total hemispherical emissivity is presented, and data for several stably oxidized metals are included. The metals which were teated included type 347 stainless steel, tungsten, and Haynes alloys B, C, X, and 25. No values of emissivity were obtained for tungsten or Haynes alloy B because of the nature of the oxides produced. The refractory oxide coatings tested were flame-sprayod alumina and zirconia. The results of the investigation indicate that strongly adherent, oxidized sunfaces of a high stable emissivity can be produced on type 347 stainless steel for which the total hemispherical emissivity varied from 0.87 to 0.91 for temperatures from 600 to 2,000 deg F. For this same temperature range, the Haynes alloys tested showed values of total hemispherical emissivity from 0.90 to 0.96 for alloy C, from 0.85 to 0.88 for alloy X, and from 0.85to 0.59 for alloy 25. Haynes alloy B and tungsten formed nonadherent oxides at elevated temperatures and, therefore, stable emissivities were net obtained. The results obtained for the flame-sprayed ceramics showed considerably higher values of total emissivity than those measured for coatings applied by other methods. Emissivity values ranging from 0.69 to 0.44 for aluminum oxide and from 0.62 to 0.44 for zirconium oxide were measured for temperatures from 800 to 2,000 deg F. (auth)
- Research Organization:
- National Aeronautics and Space Administration; Langley Research Center, Langley Field, Va.
- NSA Number:
- NSA-13-005659
- OSTI ID:
- 4275765
- Report Number(s):
- NASA-Memo-1-20-59L
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-59
- Country of Publication:
- United States
- Language:
- English
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