Trapping of deuterium by helium bubbles and defects in ion-implanted tantalum
Nuclear reaction analysis and ion implantation techniques were used to investigate the trapping of deuterium (D) by He bubbles and implantation defects in Ta. A series of four complementary temperature ramp experiments have enabled us to determine that: (1) the binding enthalpy of D at trap sites associated with He bubbles in Ta is 0.53+-0.05 eV relative to solution sites; (2) the binding enthalpies of D at implantation defects in Ta are 0.53+-0.10, 0.42+-0.10, and 0.33+-0.10 eV; and (3) the approximate number of He bubble trap sites produced per He atom implanted into Ta is 0.45 for mean He atomic fractions ranging from 1.5% to 2.5%. The measured binding enthalpies are compared with effective-medium theory calculations of the binding enthalpies of both hydrogen chemisorption sites and monovacancy sites containing from one to six trapped hydrogen atoms. This comparison suggests that the strongest 0.53-eV traps associated with implanted He are bubbles which trap hydrogen on their interior surface via a chemisorptionlike mechanism. The strong 0.53-eV defect trap sites are probably vacancy clusters, whereas the 0.42-eV defect traps appear to be monovacancy sites containing one to two hydrogen atoms, and the 0.33-eV sites appear to be monovacancy sites containing three to six hydrogen atoms.
- Research Organization:
- Sandia National Laboratories, Albuquerque, New Mexico 87185-5800(US)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6095794
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 66:3; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
BUBBLES
CHEMICAL REACTIONS
CHEMISORPTION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEUTERIUM
ELEMENTS
ENTHALPY
FLUIDS
GASES
HELIUM
HYDROGEN ISOTOPES
ION IMPLANTATION
ISOTOPES
LIGHT NUCLEI
LOW TEMPERATURE
MEDIUM TEMPERATURE
METALS
NONMETALS
NUCLEAR REACTIONS
NUCLEI
ODD-ODD NUCLEI
PHYSICAL PROPERTIES
POINT DEFECTS
RARE GASES
SEPARATION PROCESSES
SORPTION
STABLE ISOTOPES
TANTALUM
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
TRAPPING
VACANCIES