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Title: Deciphering surface behavior and deuterium retention in tin-lithium-coated fuzzy tungsten substrates

Abstract

Tungsten will be used as plasma-facing material in the divertor in ITER, but it undergoes detrimental surface-subsurface morphological changes under irradiation. One type of tungsten that may mitigate such morphologies is porous tungsten due to higher defect sink areal density. While surface nanostructures such as fuzz may compromise plasma performance, their intrinsic porosity offers a proxy for a porous material and strategies to prevent high-Z impurity emission. Liquid metal coatings have been proposed as plasma facing materials to counteract the erosion issues faced by tungsten. Tin-lithium eutectics are an understudied class of potential liquid metal coatings for their low melting points and reduced erosion and fuel retention compared to pure lithium coatings. A 95 at.% tin-lithium eutectic was deposited on fuzzy tungsten samples and exposed to 250 eV deuterium ions at 250 °C and varying fluences. Mitigation of fuzz erosion and deuterium retention were examined post-mortem with SEM and secondary mass ion spectroscopy (SIMS) of tungsten samples and witness samples used to collect eroded material. The SnLi film persisted after irradiation and protected underlying fuzz. SIMS results demonstrate surface mixing of the liquid metal and tungsten substrate and increased lithium erosion at high fluence and non-structured surfaces. The highest concentrationmore » and deepest penetration of retained deuterium was observed in the sample exposed to the lowest fluence. Results may indicate intercalation of liquid metal with tungsten tendrils at elevated temperatures.« less

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Illinois at Urbana-Champaign, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1373337
Alternate Identifier(s):
OSTI ID: 1534191
Grant/Contract Number:  
SC0014267
Resource Type:
Published Article
Journal Name:
Nuclear Materials and Energy
Additional Journal Information:
Journal Name: Nuclear Materials and Energy Journal Volume: 12 Journal Issue: C; Journal ID: ISSN 2352-1791
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English
Subject:
36 MATERIALS SCIENCE; tin-lithium; fuzzy tungsten; liquid metal; erosion; deuterium retention

Citation Formats

Lang, Eric, Kapat, Aveek, and Allain, J. P. Deciphering surface behavior and deuterium retention in tin-lithium-coated fuzzy tungsten substrates. Netherlands: N. p., 2017. Web. doi:10.1016/j.nme.2017.07.001.
Lang, Eric, Kapat, Aveek, & Allain, J. P. Deciphering surface behavior and deuterium retention in tin-lithium-coated fuzzy tungsten substrates. Netherlands. https://doi.org/10.1016/j.nme.2017.07.001
Lang, Eric, Kapat, Aveek, and Allain, J. P. Tue . "Deciphering surface behavior and deuterium retention in tin-lithium-coated fuzzy tungsten substrates". Netherlands. https://doi.org/10.1016/j.nme.2017.07.001.
@article{osti_1373337,
title = {Deciphering surface behavior and deuterium retention in tin-lithium-coated fuzzy tungsten substrates},
author = {Lang, Eric and Kapat, Aveek and Allain, J. P.},
abstractNote = {Tungsten will be used as plasma-facing material in the divertor in ITER, but it undergoes detrimental surface-subsurface morphological changes under irradiation. One type of tungsten that may mitigate such morphologies is porous tungsten due to higher defect sink areal density. While surface nanostructures such as fuzz may compromise plasma performance, their intrinsic porosity offers a proxy for a porous material and strategies to prevent high-Z impurity emission. Liquid metal coatings have been proposed as plasma facing materials to counteract the erosion issues faced by tungsten. Tin-lithium eutectics are an understudied class of potential liquid metal coatings for their low melting points and reduced erosion and fuel retention compared to pure lithium coatings. A 95 at.% tin-lithium eutectic was deposited on fuzzy tungsten samples and exposed to 250 eV deuterium ions at 250 °C and varying fluences. Mitigation of fuzz erosion and deuterium retention were examined post-mortem with SEM and secondary mass ion spectroscopy (SIMS) of tungsten samples and witness samples used to collect eroded material. The SnLi film persisted after irradiation and protected underlying fuzz. SIMS results demonstrate surface mixing of the liquid metal and tungsten substrate and increased lithium erosion at high fluence and non-structured surfaces. The highest concentration and deepest penetration of retained deuterium was observed in the sample exposed to the lowest fluence. Results may indicate intercalation of liquid metal with tungsten tendrils at elevated temperatures.},
doi = {10.1016/j.nme.2017.07.001},
journal = {Nuclear Materials and Energy},
number = C,
volume = 12,
place = {Netherlands},
year = {Tue Aug 01 00:00:00 EDT 2017},
month = {Tue Aug 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1016/j.nme.2017.07.001

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Works referenced in this record:

Deuterium retention in tungsten for fusion use
journal, October 1998


Surface composition of liquid metals and alloys
journal, November 2004


Formation of helium induced nanostructure ‘fuzz’ on various tungsten grades
journal, September 2010


Deuterium retention in tungsten in dependence of the surface conditions
journal, March 2003


Helium effects on tungsten surface morphology and deuterium retention
journal, November 2013


Sputtering properties of tungsten ‘fuzzy’ surfaces
journal, August 2011


Studies of liquid-metal erosion and free surface flowing liquid lithium retention of helium at the University of Illinois
journal, November 2004


Response of fuzzy tungsten surfaces to pulsed plasma bombardment
journal, March 2013


D, He and Li sputtering of liquid eutectic Sn–Li
journal, March 2001


Exposure of tungsten nano-structure to TEXTOR edge plasma
journal, August 2011


Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interface
journal, May 2012

  • Allain, Jean Paul; Taylor, Chase N.
  • Physics of Plasmas, Vol. 19, Issue 5
  • DOI: 10.1063/1.4719688

Tungsten as target material in fusion devices
journal, June 1996


Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions
journal, March 2015


The Li-Sn (Lithium-Tin) System
journal, January 1998


Exposures of tungsten nanostructures to divertor plasmas in DIII-D
journal, January 2016


Surface morphology and deuterium retention in tungsten exposed to high flux D plasma at high temperatures
journal, February 2015