CHEMICAL EROSION BEHAVIOR OF GRAPHITE DUE TO ENERGETIC OXYGEN IMPACT

Citation
A. Refke et al., CHEMICAL EROSION BEHAVIOR OF GRAPHITE DUE TO ENERGETIC OXYGEN IMPACT, Journal of nuclear materials, 250(1), 1997, pp. 13-22
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Nuclear Sciences & Tecnology","Mining & Mineral Processing","Material Science
ISSN journal
0022-3115
Volume
250
Issue
1
Year of publication
1997
Pages
13 - 22
Database
ISI
SICI code
0022-3115(1997)250:1<13:CEBOGD>2.0.ZU;2-O
Abstract
Pyrolytic graphite, fine grain graphite and amorphous a-C:H films were irradiated with energetic oxygen in the energy range 1-5 keV between room temperature and 1800 K. CO and CO2 molecules released during impl antation were analyzed by residual and line-of-sight mass spectroscopy and their velocity distributions were determined by time-of-flight me asurements. The retained oxygen was determined by thermal desorption s pectroscopy after irradiation. The impact of energetic oxygen (E > 1 k eV) on these materials results in the formation of CO and CO2 with an erosion yield close to unity. The observed CO release behavior can be described by a local saturation model. Special experiments indicate th at the underlying release mechanism is driven by ion-induced collision processes at the end of the ion trajectory of the impinging oxygen. T ime-of-flight measurements have shown that released CO molecules have two different energy distributions with a thermal component correspond ing to the target temperature and an overthermal component at a maximu m energy of about 0.12 eV, whereas the CO2 molecules are exclusively r eleased with thermal energies. (C) 1997 Elsevier Science B.V.