Heavy ion induced intermixing of metal/SiC interfaces

The development of new construction materials for plasma reactor walls is c rucial for the realisation and optimisation of fusion reactors. Promising c andidates are SiC-based composite materials, because their excellent high t emperature, mechanical and electrical properties may suit the high requirem ents. It is of special interest to investigate the behaviour of these mater ials under irradiation conditions. It is straightforward to use heavy ion i rradiation to simulate damage doses, which could be achieved under normal r eactor conditions with neutrons first in several years, since the damage sp ectra are very similar. Ni/SiC, Cu/SiC and Pt/SiC samples in hi-layer geome try were produced and irradiated by 150 keV Ar+ ions at fluences between 0. 75 and 4.4 x 10(16) ions/cm(2) in a temperature range between 77 and 773 K. The concentration depth profiles were obtained with Rutherford backscatter ing spectrometry (RBS). Ballistic mixing in collision cascades were observe d for all systems under investigation. In the case of the Ni/SiC system an additional mixing mechanism became dominant above room temperature. In the Pt/SiC samples radiation-induced phase formation was observed above 300 deg reesC. The sample surface was investigated with high resolution scanning el ectron microscopy (HRSEM) and atomic force microscopy (AFM). The measured s urface roughening effects were taken into account at the calculation of the mixing lengths. (C) 2001 Elsevier Science B.V. All rights reserved.