Accession Number : AD0620980

Title :   PARTIAL PRESSURES OF HG(G) AND TE2(G) IN HG-TE SYSTEM FROM OPTICAL DENSITIES,

Corporate Author : MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s) : Brebrick,R. F. ; Strauss,A. J.

Report Date : 24 NOV 1964

Pagination or Media Count : 15

Abstract : The partial pressures of Hg(g) and Te2(g) in equilibrium with Hg-saturated HgTe(c), Te-saturated HgTe(c), and some Hg-Te melts between about 400 and 700C were determined by measuring the optical density of the coexistent vapor as a function of wavelength. In agreement with mass spectrographic data, no evidence was obtained for HgTe(g) molecules. The partial pressures of the elements depend strongly on the composition of the solid phase. The maximum value of pHg in equilibrium with HgTe(c) is 19 atm, the pressure over Hg-saturated HgTe(c) between 643 and 656C. At 670C, the maximum melting point, pHg = 12.5 atm. At any temperature Hg(g) is the predominant vapor species over HgTe(c) of any composition. Liquidus temperatures for compositions between 31 and 58.5 at. %Te have been obtained from the partial pressure data, which also show that at 488C Hg-saturated HgTe(c) contains 49.9=0.2 at.% Te and Te-saturated HgTe (c) contains less than 50.5 at.% Te. The Gibbs free energy of formation of HgTe(c) from Hg(g) and Te2(g), which is practically independent of the composition of the solid phase, is found to be -41.66+42.71 (0.001) T kcal/mole. (Author)

Descriptors :   (*MERCURY, VAPOR PRESSURE), (*TELLURIUM, VAPOR PRESSURE), VAPORS, OPTICAL PROPERTIES, LIQUID METALS, PHASE STUDIES, THERMODYNAMICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE