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U.S. Department of Energy
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THERMODYNAMIC AND KINETIC STUDIES FOR A REFRACTORY MATERIALS PROGRAM

Technical Report ·
OSTI ID:4812189

Studies developed to provide thermodynamic and kinetic knowledge needed to describe the chemical behavior of zirconium and hafnium carbides and borides at temperatures to 3000 deg K and in atmospheres of O/sub 2/, O/sub 2/ + H/sub 2/ O, Cl/sub 2/, HF, F/sub 2/, H/sub 2/, CO, NH/sub 3/, and N/sub 2/ are summarized. The studies consist of thermodynamic data for the tabulation of free energy functions of the zirconium and hafnium carbides and borides through calorimetric measurements; identification of gaseous species formed on vaporization of the carbides and borides and on their interaction with the several atmospheres by mass spectrometry; therraodynamic data for important gaseous species by electron diffraction techniques, matrix isolation spectroscopy, and equilibria studies; and development of kinetics of the reactions of the carbides and borides with the various atmospheres through studies of the over-all rates of reactions and mass transport mechanisms. The status of each is discussed in detail. The preparation and characterization of macrocrystalline, high purity ZrB/sub 2/ and ZrC are described. Low temperature heat capacity data for ZrNB/sub 2/ and heat content data foi- ZrB/sub 2/, ZrC, and Hf/B/sub 2/ are presented. The results of a study of the vaporization of ZrB/sub 2/ are also reported. (auth)

Research Organization:
Little (Arthur D.) Inc. Western Div., San Francisco
NSA Number:
NSA-16-025747
OSTI ID:
4812189
Report Number(s):
ASD-TDR-62-204(Pt.I)
Country of Publication:
United States
Language:
English