skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals

Abstract

Gamma-phase lithium aluminate (gamma-LiAlO2) is a breeder material for tritium, a necessary substance for strategic stockpile and fusion power systems. A fundamental study of structural evolution and tritium diffusion in gamma-LiAlO2 under displacive irradiation is needed to fully assess the material performance. This study utilizes ion implantation of protium (surrogate for tritium) and helium in gamma-LiAlO2 single crystals at elevated temperatures to emulate the irradiation effects. The results show that at 573 K there are two distinct disorder saturation stages to 1 dpa without full amorphization; overlapping implantation of H2+ and He+ ions suggests possible formation of gas bubbles. For irradiation to 1E21 H+/m2 (0.36 dpa at peak) at 773 K, amorphization occurs at surface with H diffusion and dramatic Li loss; the microstructure contains bubbles and cubic LiAl5O8 precipitates with sizes up to 200 nm or larger. In addition, significant H diffusion and release are observed during thermal annealing.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340742
Report Number(s):
PNNL-SA-114795
Journal ID: ISSN 0022-3115; 49138; 48707; 49576; MB0503000
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 484; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
Defect accumulation; microstructure; H diffusion and release; ion implantation; tritium breeding material; lithium aluminate; Environmental Molecular Sciences Laboratory

Citation Formats

Jiang, Weilin, Zhang, Jiandong, Kovarik, Libor, Zhu, Zihua, Price, Lloyd, Gigax, Jonathan, Castanon, Elizabeth, Wang, Xuemei, Shao, Lin, and Senor, David J. Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals. United States: N. p., 2017. Web. doi:10.1016/j.jnucmat.2016.03.014.
Jiang, Weilin, Zhang, Jiandong, Kovarik, Libor, Zhu, Zihua, Price, Lloyd, Gigax, Jonathan, Castanon, Elizabeth, Wang, Xuemei, Shao, Lin, & Senor, David J. Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals. United States. doi:10.1016/j.jnucmat.2016.03.014.
Jiang, Weilin, Zhang, Jiandong, Kovarik, Libor, Zhu, Zihua, Price, Lloyd, Gigax, Jonathan, Castanon, Elizabeth, Wang, Xuemei, Shao, Lin, and Senor, David J. Wed . "Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals". United States. doi:10.1016/j.jnucmat.2016.03.014.
@article{osti_1340742,
title = {Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals},
author = {Jiang, Weilin and Zhang, Jiandong and Kovarik, Libor and Zhu, Zihua and Price, Lloyd and Gigax, Jonathan and Castanon, Elizabeth and Wang, Xuemei and Shao, Lin and Senor, David J.},
abstractNote = {Gamma-phase lithium aluminate (gamma-LiAlO2) is a breeder material for tritium, a necessary substance for strategic stockpile and fusion power systems. A fundamental study of structural evolution and tritium diffusion in gamma-LiAlO2 under displacive irradiation is needed to fully assess the material performance. This study utilizes ion implantation of protium (surrogate for tritium) and helium in gamma-LiAlO2 single crystals at elevated temperatures to emulate the irradiation effects. The results show that at 573 K there are two distinct disorder saturation stages to 1 dpa without full amorphization; overlapping implantation of H2+ and He+ ions suggests possible formation of gas bubbles. For irradiation to 1E21 H+/m2 (0.36 dpa at peak) at 773 K, amorphization occurs at surface with H diffusion and dramatic Li loss; the microstructure contains bubbles and cubic LiAl5O8 precipitates with sizes up to 200 nm or larger. In addition, significant H diffusion and release are observed during thermal annealing.},
doi = {10.1016/j.jnucmat.2016.03.014},
journal = {Journal of Nuclear Materials},
number = C,
volume = 484,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}
  • RBS/Channeling has been used to study the accumulation and isochronal recovery of disorder on the Si sublattice in 6H-SiC single crystals irradiated with 100 keV H₂⁺ ions at 100 and 300 K. The disorder at the damage peak shows a sigmoidal dependence on ion fluence for both irradiation temperatures. Dramatic simultaneous recovery is observed for the irradiation at 300 K. At low fluences, isochronal recovery occurs gradually over a wide temperature range. At high fluences, a near amorphous state is produced, and significant recovery does not occur. At intermediate fluences, damage recovery occurs more rapidly between 300 and 670 K.more » Further annealing at 1070 K results in the formation of blisters. Hydrogen depth profiles at 100 and 300 K are comparable and are well predicted by SRIM-97 simulations. Hydrogen release of about 30% is observed for SiC irradiated at 100 K and subsequently annealed at 1070 K for 20 min.« less
  • The radiation chemistry of aqueous solutions containing nitrous oxide was investigated to determine the forms of hydrogen atoms produced by gamma rays. Some of the results for ferrous sulfate solutions are shown, from which it is evident that: (a) G(F/sup 3+/) has the same value in the deaerated nitrous oxide-containing solution as in the nitrous oxidefree solution; (b) the total gas yield is the same in both systems and equal to GH + GH; (c) in the N/sub 2/O- containing system some nitrogen is always produced and the ratio 2 and then rises sharply with further increases. The value ofmore » G(N/sub 2/) at pH> 2.7 is that expected on the hypothesis that all the available hydrogen atoms are scavenged by N/sub 2/O in a reaction of one mole of N/sub 2/ for every mole of H/sub 2/ scavenged. The fact that G(N/sub 2/) does not become zero at pH < 2 is interpreted as evidence for the existence of two dif- . ferent species of H atom, only one of which is capable of reducing N/sub 2/O in this low pH range. (B.O.G.)« less
  • This work reports on the effects of a deep high-dose hydrogen ion implant on damage accumulation, defect retention, and silver diffusion in silver implanted ZnO crystals. Single-crystal ZnO samples were implanted with Ag ions in a region ∼150 nm within the surface, and some of these samples were additionally implanted with hydrogen ions to a dose of 2 × 10{sup 16 }cm{sup −2}, close to the depth ∼250 nm. Rutherford backscattering/ion channeling measurements show that crystal damage caused by Ag ion implantation and the amount of defects retained in the near surface region following post-implantation annealing were found to diminish in the case with themore » H implantation. On the other hand, the additional H ion implantation resulted in a reduction of substitutional Ag atoms upon post-implantation annealing. Furthermore, the presence of H also modified the diffusion properties of Ag atoms in ZnO. We discuss these findings in the context of the effects of nano-cavities on formation and annihilation of point defects as well as on impurity diffusion and trapping in ZnO crystals.« less