THERMODYNAMICS OF FORMATION OF ThMg$sub 2$

Technical Report · Fri Jan 11 04:00:00 EST 1963

OSTI ID:4638825

Novotny, D B; Smith, J F

The thermodynamic functions for the formation of ThMg/sub 2/ were determined by measuring the equilibrium vapor pressure of Mg over Th--ThMg/sub 2/ two-phase alloys at 692to 812 deg K. The data show that for the reaction ThMg/sub 2/(s) in equilibrium 2Mg(g) + Th(s), the vapor pressure may be expressed as log/ sub 10/p (mm Hg) = (--9130 plus or minus 210)/T + 10.3 plus or minus 0.3. This equation and the vapor pressure of pure solid Mg were used to obtain the free energy of formation of ThMg/sub 2/ from the pure solid elements: DELTA F deg (kcal/mole) = -- 14.3 plus or minus 3.1 + (15.2 plus or minus 4.3) x 10/ sup -3/ T. This equation indicates that ThMg/sub 2/ should be unstable above 942 deg K, which is considerably below the observed peritectic reaction at 780 deg C. A tentative revision of the equation gives F deg = --15.2 plus or minus 14.4 x 10/sup -3/ T. (D.L.C.)

• Research Organization: Ames Lab., Ames, Iowa
• DOE Contract Number: W-7405-ENG-82
• NSA Number: NSA-17-035686
• OSTI ID: 4638825
• Report Number(s): IS-589
• Country of Publication: United States
• Language: English

Related Subjects

ALLOYS
CHEMICAL REACTIONS
CHEMISTRY
EQUATIONS
INTERMETALLIC COMPOUNDS
MAGNESIUM COMPOUNDS
PRESSURE
PRODUCTION
SOLIDS
THERMODYNAMICS
THORIUM COMPOUNDS
VAPORS