Chemical erosion of carbon doped with different fine-grain carbides

Several carbide-doped (SiC, TiC, V8C7, WC, ZrC) graphites have been produce d. The erosion of these materials at low-energy (eV) hydrogen ion bombardme nt has been investigated using the weight-loss method, mass spectroscopy, i on beam analysis, and scanning electron microscopy (SEM). The erosion yield s of the WC- and V8C7-doped graphites are reduced by a factor of 2 for 30 e V D at 300 K compared to pure graphite. This observed reduction is partly a ttributed to surface enrichment of carbide due to preferential C erosion. T he other part is assigned to changes in the chemical erosion process (Y-sur f) as well as at elevated temperatures in the thermal activated process (Y- therm). The reduction of both erosion processes is determined for all dopan ts to be more than 25% of the erosion yield of the undoped graphite. (C) 20 01 Elsevier Science B.V. All rights reserved.