EFFECT OF 690-KEV XE ION IRRADIATION ON THE MICROSTRUCTURE OF AMORPHOUS MOSI2/SIC NANOLAYER COMPOSITES

The effect of 690 keV Xe ion irradiation at three different dosage levels, 1, 5 and 10{times}10{sup 15}/cm{sup 2}, on the microstructure of amorphous-MoSi{sub 2}/amorphous-SiC nanolayer composites has been studied using transmission electron microscopy. Results show that the depth of radiation damage in this multilayer material is {approximately}80 nm, which agrees qualitatively well with the calculated damage depth calculated by TRIM. A diffraction ring corresponding to the (10{bar 1}1) plane of C40 MoSi{sub 2} was found in the electron diffraction pattern taken from the irradiated regions; the C40 phase is also found after thermal annealing of amorphous MoSi{sub 2} at 500{degrees}C or above. In the damaged regions SiC layers were found to spherodize while the nanocrystalline grains in the MoSi{sub 2} layers appeared to coarsen with increasing dose.