Activity of hydrogen in metal-hydrogen systems: strontium, thorium-nitrogen and vanadium alloys

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5512456

Nelson, S O

The dissolution of hydrogen gas has been studied by means of hydrogen pressure-composition isotherms in strontium, thorium-nitrogen and vanadium alloys containing either niobium, chromium or titanium. Direct hydrogen equilibrium vapor pressure measurements were performed in the strontium-hydrogen and thorium-nitrogen-hydrogen systems in the ranges 973 to 1173 K and 623 to 1123 K, respectively. An indirect method, an isopiestic solubility technique, was employed to measure the hydrogen equilibrium pressures for the vanadium alloys in the range 223 to 473 K. In all the alloys studied, the reaction of hydrogen with the metal phase was exothermic and hydrogen followed Sieverts' law over a considerable range of hydrogen concentration. The enthalpy of solution of hydrogen in the strontium metal and the enthalpy of formation of ThNH/sub x/ were determined to have the values of -14.3 +/- 1.2 kcal/mol H and -16.3 +/- 1.5 kcal/mol H/sub 2/, respectively. The values of the enthalpies of solution of hydrogen for the vanadium alloys ranged from -8.0 to -10.5 +/- 0.3 kcal/mol H. Additions of titanium to vanadium dramatically enhanced the isopiestic solubility of hydrogen, chromium significantly reduced the solubility and niobium moderately increased the solubility. Sieverts' law behavior for hydrogen in the vanadium alloys showed that substitutional atoms did not act as deep traps for hydrogen.

• OSTI ID: 5512456
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
ACTINIDE ALLOYS
ALLOYS
CHEMICAL REACTIONS
DATA
ELEMENTS
ENTHALPY
EXPERIMENTAL DATA
HYDROGEN
HYDROGENATION
INFORMATION
ISOTHERM
NITROGEN ADDITIONS
NONMETALS
NUMERICAL DATA
PHYSICAL PROPERTIES
SOLUBILITY
SOLUTION HEAT
STRONTIUM ALLOYS
THERMODYNAMIC ACTIVITY
THERMODYNAMIC PROPERTIES
THORIUM ALLOYS
VANADIUM ALLOYS
VAPOR PRESSURE