THERMODYNAMIC PROPERTIES OF NONSTOICHIOMETRIC NICKEL TELLURIDES AND OF TELLURIUM (thesis)
As part of a thermodynamic study of NiTe and NiTe/sub 2/, an attempt was made to gather data which would determine zero-point entropies as a function of composition. Part of the necessary data have been gathered, and in addition a number of other pertinent or interesting properties of the nickel tellurides, and of Te, have been investigated. Specific heats from 4 to 350 deg K have been measured on NiTe/sub 1.1/ NiTe/sub 1.5/, and NiTe/sub 2.0/, and the thermodynamic functions of these and all intermediate compositions may be considered accurately known over this temperature range. The method employed was conventional precise adiabatic calorimetry in an existing apparatus. The melting point of Te has been redetermined and the highly discordant literature critically reexamined; the triple point may now be stated with some confidence to be 449.7 plus or minus 0.2 deg C. The dissociation pressures of compositions from NiTe/sub 1.5/ to NiTe/ sub 2.0/ have been accurately measured at temperatures up to 780 deg C in order to determine the partial molal free energies and entropies of Te in these compounds. These measurements have incidentally elucidated the phase behavior in the Te-rich region, showing a high solubility of Ni in liquid Te at elevated temperatures, and incongruent melting of the solid solutions such that Te-rich solid solutions are unstable at elevated temperatures. By extrapolation, the boiling point of Te is computed to be 993.6 plus or minus 2 deg C. and the heat of vaporization to be 33,850-908 t cal/mole (one mole equals two gram-atoms). with an accuracy of plus or minus several hundred calories, from the triple point to t = 850 deg , or perhaps 950 deg C. This figure may be considered more accurate, though stated with less precision, than those of previous investigators. (auth)
- Research Organization:
- Michigan. Univ., Ann Arbor
- DOE Contract Number:
- AT(11-1)-70
- NSA Number:
- NSA-12-006603
- OSTI ID:
- 4330908
- Report Number(s):
- AECU-3636
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE VAPORIZATION AND PHYSICAL PROPERTIES OF CERTAIN REFRACTORIES. PART I. TECHNIQUES AND PRELIMINARY STUDIES
Partial pressures over the pseudobinary solid solution Hg /SUB 1-x/ Cd /SUB x/ Te(s) for x=0. 70 and 0. 95 and over four Te-rich ternary melts