Diamond deposition on steel substrates with an Al interlayer

The feasibility of using Al films as interlayers for growing high quality diamond on stainless steel substrates has been examined using a microwave plasma enhanced CVD reactor. The as-coated Al intermediate film significantly improved the nucleation and phase purity of diamond at early stages of growth on the steel. Graphite phase, which usually grows preferentially on bare steel substrate, was effectively prevented due to this Al interlayer. A direct scratching pretreatment by diamond suspension was not applicable to this Al-coated steel, as soft Al surface film could be partially removed, resulting in discontinuous diamond films. To overcome this disadvantage, a vacuum interdiffusion annealing process of the Al-coated steel, followed by diamond scratching treatment, enabled the deposition of continuous, dense, and adherent diamond films on Al-interlayered stainless steel substrates.