Surface studies of SiC/SiCf composites exposed to relevant fusion reactor conditions

Abstract

SiC/SiC f ceramic composites are interesting materials for applications in fusion technology due to their high performance and low activation characteristics. Combining microbeam RBS and proton-induced x-ray emission (PIXE) with XPS and x-ray diffraction techniques, we study the structural changes that occurred in SiC/SiC f composites exposed to Li silicate and Li titanate breeder materials in fusion-relevant conditions. After 216 h of exposure at 800 °C the RBS spectra show the surface oxidation in all composites. Diffusion of Li and Ti into the composites was also observed. After 1000 h, the oxide layer extends for several micrometres. Microbeam analyses show the presence of titanium-rich precipitates in the samples exposed to the Li 2 TiO 3 ceramic breeder, together with some iron contamination. The x-ray diffraction spectra reveal the formation of SiO 2 and some Li-rich phases. These findings are supported by the results of the XPS measurements.