TIN BUFFER LAYERS PREVENTING FE DIFFUSION FROM STAINLESS-STEEL

Two kinds of reactively evaporated titanium nitride films with columna r (B-o films) and fine-grained (B+ films) film structures respectively have been examined as diffusion barriers preventing iron diffusion fr om stainless steel. The iron diffusion profiles have been investigated by 2 MeV(4)He(+) Rutherford backscattering spectrometry (RBS) at temp eratures up to 600 degrees C. The diffusivity from 300 to 600 degrees C is D[m(2).s.(-1)] = 1.8 x 10(-8).exp[-17/(RT)] in B-o layers and D [ m(2).s(-1)] = 5.8 x 10(-18).exp[-38/(RT)] in B-+ TiN layers. The diffu sivities determined correspond to grain boundary diffusion, the differ ence is a result of the different film microstructure. The low Fe diff usivity in B-+ TiN layer makes it an efficient buffer layer for high-T -c superconductivity power applications.