Alloying effect on a property of hydrogen gettering materials: An empirical formula to estimate heat of hydride formation for metals and alloys
Getter materials are promising for the research and development of thermonuclear fusion reactors from a viewpoint of tritium handling as well as fuel and impurity control in tokamaks. Some guiding rules are indispensable in developing a getter material having suitable properties for a given process in tritium handling. In analogy to the relation between the heat of oxide formation and electronegativities of elements, we studied the change in the heat of hydride formation with metals and alloys from this viewpoint: the electronegativities of getter materials and hydrogen. We found a simple relation between them in a form of (/minus/..delta../ital H//sub abs/)=23/ital s/(xi/sub /ital M///minus/2.20)/sup 2/ +3.72/ital s//minus/3.72, where xi/sub /ital M// and 2.20 are the electronegativities of getter material and hydrogen, and /ital s/ is the stoichiometric number of hydrogen in hydride. The standard deviation from the observed values was /similar to/5 kcal/mol(hydride) and/or 35%. This equation was found to be valid for 70 systems which appear to form metallic hydride. An advantage of this equation can be seen in the fact that it consists of only the electronegativities of getter materials and hydrogen, and the stoichiometric number of hydrogen, both of which can be found in literature or estimated with simple assumptions. Consequently, it will be quite useful as a guiding rule to design a getter material with a given heat of hydride(tritide) formation for metals/alloys and/or heat of hydrogen(tritium) absorption.
- Research Organization:
- Tritium Research Center, Toyama University, Gofuku 3190, Toyama 930, Japan(JP)
- OSTI ID:
- 6140575
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 7:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GETTERING
HYDRIDES
FORMATION HEAT
THERMONUCLEAR REACTORS
VACUUM SYSTEMS
ABSORPTION
ALLOYS
ELECTRONEGATIVITY
EQUATIONS
IMPURITIES
METALS
ELEMENTS
ENTHALPY
HYDROGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
THERMODYNAMIC PROPERTIES
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