High-temperature spectral emissivity of several refractory elements and alloys

  • R. N. Wall
  • D. R. Basch
  • D. L. Jacobson


Thermionic energy conversion has emerged as the method of choice for the direct space-based conversion of heat to electricity. An important parameter in the implementation of this method of direct energy conversion is the emissivity of the converter emitter and collector materials. This information is necessary to determine heat losses, heat transfer, and reservoir temperatures in the thermionic energy converter. Spectral normal emissivities were acquired at a wavelength of 0.65 ώm for a series of tungsten-rhenium alloys, tungsten-osmium alloys, and tungsten-iridium alloys in the temperature range 1400 to 2600 K. Additionally, the spectral normal emissivity for pure elements of molybdenum and ruthenium were obtained over the temperature range 1200 to 2600 K and 1400 to 2250 K, respectively. The spectral normal emissivities for a niobium-67% ruthenium (eutectic composition) in the temperature range 1400 to 2000 K were also obtained at the same wavelength. In all cases, the emissivity decreased linearly with increasing temperature. Both the tungsten-osmium and the tungsten-rhenium alloys exhibited emissivity values of 0.32 to 0.54 over the temperatures tested. The tungsten-iridium alloy yielded emissivity data of 0.35 to 0.47. The niobium-ruthenium emissivity data were within 0.34 and 0.36. The pure molybdenum and pure ruthenium experiments resulted in emissivity values ranging from 0.35 to 0.45 and 0.35 to 0.39, respectively.


Emissivity Iridium Tungsten Alloy Spectral Normal Emissivity Pure Molybdenum 
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Copyright information

© ASM International 1992

Authors and Affiliations

  • R. N. Wall
    • 1
  • D. R. Basch
    • 2
  • D. L. Jacobson
    • 2
  1. 1.Advanced Semiconductor Technology CenterIBM East Fishkill Facility, Hopewell Junction
  2. 2.Department of Chemical, Bio, and Materials EngineeringArizona State UniversityTempe

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