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Abstract

Boron and carbon sublime from a boron-doped carbon (3.8 % B, Carbon Loraine S1122) as from an independent mixture of the two components. The boron sublimation occurs with an activation energy of 5.3 eV, nearly equal to that of pure boron (5.6 eV). The amount of sublimed boron is 1 % of that of pure boron and decreases with time by t(-0.5) indicating a diffusion controlled process. This boron-doped carbon contains impurities which are thermally desorbed in peaks centred at the following temperatures: Ca (100 ppm) at 1870 K, O as CO (115 ppm) at 1750 K, Al (83 ppm) at 2050 K, Mg (22 ppm) at 1600 K. The comparison of these sublimation data with the high temperature erosion by ion impact under high flux tokamak conditions results in the following predictions for the release of boron and carbon from boron-doped carbon: up to 2100 K the erosion is dominated by ion effects (RES, boron sputtering); above 2300 K boron is released mainly by thermal sublimation; at 3000 K the thermal sublimation of carbon reaches the same value as for the carbon release by RES.

Additional information

Authors: VIETZKE E, Forschungszentrum Jülich GmbH, Institut für Plasmaphysik (DE);PHILIPPS V, Forschungszentrum Jülich GmbH, Institut für Plasmaphysik (DE);FLASKAMP K, Forschungszentrum Jülich GmbH, Institut für Plasmaphysik (DE)
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 196-198 (1992) pp. 1112-1117
Record Number: 199310257 / Last updated on: 1994-11-29
Category: PUBLICATION
Original language: en
Available languages: en