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Report on the study of erosion and H-recycle/inventory of carbon/graphite

Technical Report:

Abstract

This study investigated the erosion and hydrogen retention capacity of graphite under plasma exposure by performing controlled plasma simulation experiments using a low-energy high-flux mass analyzed ion accelerator. The authors studied radiation-enhanced sublimation (RES) of graphite, the effect of ion angle of incidence on physical sputtering, the effect of oxygen on hydrocarbon formation during O{sub 2}/H{sup 2} impact, chemical erosion of boron carbide, and the effect of thermal atoms on self-sputtering of graphite. The flux dependence of RES is nearly linear (power of .91) for the extended flux range of 10{sup 13} - 10{sup 17} H{sup +}/cm{sup 2}s. Physical sputtering yields were enhanced for off-normal angles of incidence, especially for highly-oriented polished surfaces. Oxygen did not appear to have an effect on the hydrocarbon formation rate; however, some erosion through CO formation was observed. Although large transients were observed in hydrocarbon production in B{sub 4}C, steady-state levels were typically about two orders of magnitude below the erosion rate of graphite. To investigate carbon self-sputtering, thermal H{sup 0} atoms were added to impacting C{sup +} ions, simulating a condition existing in the tokamak plasma edge. This led to a synergistic enhancement of the chemical erosion process.Work on hydrogen retention concentrated on  More>>
Authors:
Haasz, A A; Davis, J W [1] 
  1. Toronto Univ., ON (Canada). Inst. for Aerospace Studies
Publication Date:
Apr 01, 1990
Product Type:
Technical Report
Report Number:
CFFTP-G-9034
Reference Number:
SCA: 700420; 400201; 360604; PA: AIX-23:003891; SN: 91000604840
Resource Relation:
Other Information: PBD: Apr 1990
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; GRAPHITE; EROSION; BORON CARBIDES; HYDROGEN IONS 1 PLUS; ION BEAMS; SPUTTERING; SUBLIMATION; TRAPPING; 700420; 400201; 360604; PLASMA-FACING COMPONENTS; CHEMICAL AND PHYSICOCHEMICAL PROPERTIES; CORROSION, EROSION, AND DEGRADATION
OSTI ID:
10105235
Research Organizations:
Canadian Fusion Fuels Technology Project, Toronto, ON (Canada)
Country of Origin:
Canada
Language:
English
Other Identifying Numbers:
Other: ON: DE92608692; TRN: CA9110925003891
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
INIS
Size:
29 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Haasz, A A, and Davis, J W. Report on the study of erosion and H-recycle/inventory of carbon/graphite. Canada: N. p., 1990. Web.
Haasz, A A, & Davis, J W. Report on the study of erosion and H-recycle/inventory of carbon/graphite. Canada.
Haasz, A A, and Davis, J W. 1990. "Report on the study of erosion and H-recycle/inventory of carbon/graphite." Canada.
@misc{etde_10105235,
title = {Report on the study of erosion and H-recycle/inventory of carbon/graphite}
author = {Haasz, A A, and Davis, J W}
abstractNote = {This study investigated the erosion and hydrogen retention capacity of graphite under plasma exposure by performing controlled plasma simulation experiments using a low-energy high-flux mass analyzed ion accelerator. The authors studied radiation-enhanced sublimation (RES) of graphite, the effect of ion angle of incidence on physical sputtering, the effect of oxygen on hydrocarbon formation during O{sub 2}/H{sup 2} impact, chemical erosion of boron carbide, and the effect of thermal atoms on self-sputtering of graphite. The flux dependence of RES is nearly linear (power of .91) for the extended flux range of 10{sup 13} - 10{sup 17} H{sup +}/cm{sup 2}s. Physical sputtering yields were enhanced for off-normal angles of incidence, especially for highly-oriented polished surfaces. Oxygen did not appear to have an effect on the hydrocarbon formation rate; however, some erosion through CO formation was observed. Although large transients were observed in hydrocarbon production in B{sub 4}C, steady-state levels were typically about two orders of magnitude below the erosion rate of graphite. To investigate carbon self-sputtering, thermal H{sup 0} atoms were added to impacting C{sup +} ions, simulating a condition existing in the tokamak plasma edge. This led to a synergistic enhancement of the chemical erosion process.Work on hydrogen retention concentrated on the study of H{sup +} trapping in different types of graphites as a function of flux and fluence of incident H{sup +}. The amount of H trapped in the near-surface region of graphite reaches a saturation level, a function of graphite temperature and impacting H{sup +} energy. The amount of H trapped in graphite beyond the ion range was found to increase with increasing fluence. It seems that hydrogen diffuses through grain boundaries and open porosity in the material until trapped by available carbon bonds.}
place = {Canada}
year = {1990}
month = {Apr}
}