Effect of microstructure in metal reinforced composite CVD diamond films on mechanical properties

Comparison of behavior observed during deadhesion of CVD diamond films and compositional analysis of their microstructure allows a correlation between microstructure and mechanical behavior to be made. Diamond films were grown in a DC Triple Torch Reactor using a mixture of methane and hydrogen on molybdenum substrates. To address the issue of voids at the interface, a metal binder was electroplated after the nucleation of individual diamond crystals on the substrates. The films were completed by growing a layer of diamond upon the composite layer. Interfacial composition and structure of the films are characterized by a x-ray, Auger, and Raman spectroscopy. A carbide may act to enhance the adhesion via chemical bonding between the substrate and film. Diffusion of the binder into the substrate and film is also important for mechanical properties and is confirmed by x-ray mapping. It is suggested that a diamond like carbon layer acts to enhance the adhesion of the film to the substrate.