Plasma and Fusion Research
Online ISSN : 1880-6821
ISSN-L : 1880-6821
Regular Articles
Chemical Binding States of Carbon Atoms Migrated in Tungsten Coating Layer Exposed to JT-60U Divertor Plasmas
Masakatsu FUKUMOTOTomohide NAKANOYoshio UEDAKiyoshi ITAMI
Author information

2013 Volume 8 Pages 1405159


Carbon migration in the tungsten coating layer exposed to JT-60U divertor plasmas has been investigated by analysis of chemical binding states of the carbon atoms. More than 1% of carbon atoms were accumulated as graphitic carbon, amorphous carbon and/or carbon-deuterium bonds. This concentration was more than five orders of magnitude higher than the solubility of carbon atoms in tungsten lattice. Up to 20% of ditungsten carbide (W2C) was also formed in the tungsten coating layer. These findings suggested the following carbon migration mechanism in the tungsten coating layer. The incident carbon migrates along grain boundaries and defects such as pores over the depth which is evaluated by the carbon diffusion coefficient in tungsten lattice. The carbon atoms trapped on grain surface penetrate and diffuse in the grains. The carbon atoms exceeded the solubility of carbon atoms in tungsten lattice chemically bind to tungsten atoms and form W2C.

Content from these authors
© 2013 by The Japan Society of Plasma Science and Nuclear Fusion Research
Previous article Next article