Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-25T17:38:03.119Z Has data issue: false hasContentIssue false
  • English
  • Français

Containerless Study of Metal Evaporation by Laser Induced Fluorescence

Published online by Cambridge University Press:  26 February 2011

Robert A. Sghiffman  and
Paul C. Nordine
Robert A. Sghiffman
Affiliation:
Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 64110
Paul C. Nordine
Affiliation:
Midwest Research Institute, 425 Volker Boulevard, Kansas City, MO 64110
Get access

Abstract

Laser induced fluorescence (LIF) detection of atomic vapors was used to study evaporation from electromagnetically levitated and CW CO2 laser heated molydenum spheres and resistively heated tungsten filaments. Electromagnetic (EM) levitation in combination with laser heating of tungsten, zirconium, and aluminum specimens was also investigated. LIF intensity vs temperature data were obtained for molybdenum ( 7S3 ) atoms and six electronic states of atomic tungsten, at temperatures up to the melting point of each metal. The detected fraction of the emitted radiation was reduced by self-absorption effects at the higher experimental temperatures.Vaporization enthalpies derived from data for which less than half the LIF intensity was self-absorbed were ΔHo0 = -636 ± 24 kJ/g-mol for Mo and 831 ± 32 kJ/g-mol for W. Space-based applications of EM levitation in combination with radiative heating are discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 87: Symposium O – Materials Processing in the Reduced Gravity Environment of Space , 1986 , 339
Copyright
Copyright © Materials Research Society 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Nordine, P. C. and Schiffman, R. A., Adv. Ceram. Materials, to be published.Google Scholar
2. Espe, W., Materials of High Vacuum Technology, Vol.1, Pergamon, New York, 1966.Google Scholar
3. Fromm, E. and Jehn, H., Brit. J. Appl. Phys. 16, 653 (1965).Google Scholar
4. Moore, C. E., Atomic Energy Levels, NBS Circular No. 467, Vols. 1–3, U. S. Govt. Printing Office, Washington, DC, 1971.Google Scholar
5. Stull, D. R. and Prophet, H., JANAF Thermochemical Tables, 2nd ed., Nat. Stand. Ref. Data Ser., Nat. Bur. Stand., 37, U. S. Govt. Printing Office, Washington, DC, 1971.Google Scholar
6. Nordine, P. C. and Schiffman, R. A., High Temp. Sci. 20, 1–20 (1985).Google Scholar
7. Mitchell, A. C. G. and Zemansky, M. W., Resonance Radiation and Excited Atoms, Cambridge University Press, London, 1934.Google Scholar