Vaporization Thermodynamics of Chromium Silicides.

Abstract

The vaporization thermodynamics of the chromium-silicon system have been investigated in the temperature range 1300-1600K by Knudsen cell mass spectrometry. Both magnetic sector and quadrupole instruments were employed. Thermodynamic activities were obtained by direct comparison with the elements. Standard free energies of formation at 1500K, Delta G deg (sub f)/R (kilokelvins) are: 1/3 CrSi2, -3.07; 1/2 CrSi, -3.62; 1/8 Cr5Si3, -3.73; 1/4 Cr3Si, -3.28. These data, when combined with heat capacity and entropy data from the literature, give standard enthalpies of formation at 298.15K, Delta H deg (sub f)/R (kilokelvins): 1/3 CrSi2, -3.36; 1/2 CrSi, -3.20; 1/8 Cr5Si3, -3.38; 1/4 Cr3Si, -3.39. The CrSi2 phase was found to contain the congruently vaporizing composition. Keywords: Chromium silicides, vaporization thermodynamics, free energy of formation, enthalpy of formation, congruent vaporization, Knudsen effusion, mass spectrometry.

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Document Details

Document Type
Technical Report
Publication Date
Nov 26, 1985
Accession Number
ADA162286

Entities

People

  • C. E. Myers
  • G. A. Murray
  • M. A. Frisch
  • R. J. Kematick

Organizations

  • Binghamton University

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Abstracts
  • Chemical Analysis
  • Chemistry
  • Chromium
  • Corrosion Resistance
  • Elements
  • Energy
  • Enthalpy
  • Free Energy
  • Heat Capacity
  • Heat Energy
  • High Temperature
  • Mass Spectrometers
  • Mass Spectrometry
  • Measurement
  • Spectrometry
  • Thermodynamics

Readers

  • Combustion science or combustion engineering.
  • Materials Science and Engineering.