SiC films on stainless steel prepared by ion beam mixing were irradiated to 1×1018 ions/cm2 by 5 kV H+ beam. Secondary ion mass spectrometry (SIMS) was used for depth profiling of H+ and mass spectra of positive species in the samples. The property of SiC films’ hydrogen resistance and the mechanism were studied. The permeability coefficient was measured to confirm the capability of tritium resistance. It was found that the SiC films on stainless steel show good retarding effects on the permeation of hydrogen isotopes. The tritium permeability is reduced by 4~5 orders of magnitude

and the hydrogen resistance of SiC films is the result of C-H

C-H2

C-H3

Si-H

Si-H2 and Si-H3 in the films.