GROWTH OF DIAMOND FILMS ON STAINLESS-STEEL

Continuous diamond films have been deposited on 304 stainless steel with a silicon intermediate layer by means of hot-filament chemical vapor deposition. The most serious problems for growing diamond films on ferrous metals are a long nucleation period, the catalytic effect of iron, and thermal expansion mismatch. In order to reduce these unwanted effects, three approaches have been adopted. First, an intermediate layer was used to block carbon diffusion, enhance adhesion and suppress sp2 carbon formation. Second, oxygen-assisted low temperature deposition was used to minimize the thermal expansion effect and also avoid the phase transition of iron alloys. Third, initial and secondary nucleation was enhanced to field small grain sizes in the continuous film. The morphology and quality of the deposited films were characterized by scanning electron microscopy and Raman spectroscopy respectively. Pull-off adhesion tests showed that the intermediate layer was strongly bonded to both the steel substrate and diamond film.