[Table of Contents]

Plasma and Fusion Research

Volume 5, 003 (2010)

Rapid Communications

Chemical Erosion of Diamond-Coated Graphite under Low-Energy Hydrogen Atom Irradiation
Yuji TAKEGUCHI, Masaaki KYO, Yoshihiko UESUGI, Yasunori TANAKA and Suguru MASUZAKI1)
Division of Electrical and Computer Science Kanazawa University, Kanazawa 920-1192, Japan
1)
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 23 July 2009 / Accepted 7 November 2009 / Published 25 January 2010)

Abstract

We experimentally investigate chemical erosion of polycrystalline graphite targets coated with boron-doped diamond (BDD) using an induction plasma containing low-energy, high-atomic-hydrogen flux. Chemical erosion is drastically suppressed by diamond coating the graphite target. The chemical sputtering yield for the BDD layer is about two orders of magnitude lower than that for the graphite target. After exposure in low-temperature hydrogen plasmas, however, the surface morphology of the BDD target is significantly modified. The polycrystalline diamond is eroded near the grain boundary, and many pits with diamond-like shapes are observed on the crystal surface. X-ray photoelectron spectroscopy and Raman spectroscopy reveal that the hydrogen atoms penetrate into the BDD target to a depth of at least ∼20 nm.

Keywords

chemical erosion, plasma-material interaction, boron-doped diamond, graphite

DOI: 10.1585/pfr.5.003

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This paper may be cited as follows:

Yuji TAKEGUCHI, Masaaki KYO, Yoshihiko UESUGI, Yasunori TANAKA and Suguru MASUZAKI, Plasma Fusion Res. 5, 003 (2010).