Chemical sputtering studies of lithiated ATJ graphite

Plasma Facing Component (PFC) materials are crucial to fusion reactor development. There is no one material that functions as an ideal PFC material. As a result, coatings are applied to control the interaction between plasmas and the PFC material. Lithium wall conditioning treatments in the National Spherical Torus Experiment have shown dramatic improvements in plasma performance. In order to understand the complex system of lithiated ATJ graphite, chemical sputtering measurements of plain and lithiated ATJ graphite have been conducted in IIAX (Ion-surface InterAction eXperiment) facility. Chemical sputtering of graphite is dependent on the ion energy and substrate temperature, hence the total effects of treating ATJ graphite with lithium in hydrogen plasma are investigated in terms of different target temperatures and bias voltages. The dominant chemical sputtering product is Methane (CH4). It was found that lithium treatments have suppressed the chemical sputtering of ATJ graphite. The suppression of chemical sputtering effect as function of varying lithium thickness on ATJ graphite has been thoroughly studied. The experimental data suggests that the thickness of the lithium has to be greater than the surface roughness of the ATJ graphite to see substantial suppression in chemical sputtering.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2013

Author dc:creator

• Raman, Priya

Contributors dc:contributor

• Ruzic, David N.

• ATJ graphite
• Lithium
• Chemical sputtering
• Chemical erosion

Statement dc:rights

• Copyright 2012 Priya Raman

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/42432

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/42432