INVESTIGATION OF DIAMOND THIN-FILM GROWTH ON FERROUS SURFACES

It is widely understood that iron-, nickel- and cobalt-based materials have a surface catalytic reaction with carbon. The reaction results in diffusion of carbon into these materials, forming carbides. It has been reported that this catalytic effect will give rise to poor nucleation of diamond particles on the above materials. However, there has recently been a report that shows otherwise. It was said that the diffusion of carbon species into iron surfaces enhances the nucleation density of diamond particles and that the nucleation density is also a function of the thickness of the iron layer. In view of the above, a detailed study has been carried out to investigate the nucleation and growth of diamond on iron surfaces by microwave-plasma-enhanced chemical vapour deposition. Mirror-finished silicon substrates with a vacuum-deposited layer of iron have been used to initiate the nucleation of diamond. The thickness of the iron is varied in the experiment to study its effect on the nucleation density. The effects of surface treatment of the stainless steel substrate on the nucleation of diamond have been investigated with diamond-paste-polished, unpolished and silicon-coated substrates. The diamond films have been examined by scanning atomic force microscopy, scanning electron microscopy and Raman spectroscopy.