Chemical erosion of carbon doped with different fine-grain carbides

Several carbide-doped (SiC, TiC, V8C7, WC, ZrC) graphites have been produced. The erosion of these materials at low-energy (eV) hydrogen ion bombardment has been investigated using the weight-loss method, mass spectroscopy, ion beam analysis, and scanning electron microscopy (SEM). The erosion yields of the WC- and V8C7-doped graphites are reduced by a factor of 2 for 30 eV D at 300 K compared to pure graphite. This observed reduction is partly attributed to surface enrichment of carbide due to preferential C erosion. The other part is assigned to changes in the chemical erosion process (Ysurf) as well as at elevated temperatures in the thermal activated process (Ytherm). The reduction of both erosion processes is determined for all dopants to be more than 25% of the erosion yield of the undoped graphite.