Influence of Substrate Temperature and Surface Morphology of CR-N Interlayer on The Adhesion of Diamond Coatings on WC-CO Substraters

Physical and Analytical Chemistry Seminar

Lecturer: Miri Fischer Horowitz

27 Jul 2016 @ 11:00

Location: Faculty Seminar Room

The possibility of combining the hardness of diamond with the toughness of WC–Co has attracted a great attention toward the deposition of diamond films on WC–Co substrates due to their potential industrial applications. However, the performance of diamond coated WC–Co machining tools is limited by the coating-substrate adhesion strength. In this work, we investigated the effect of substrate temperature and surface morphology of Cr-N interlayer on the adhesion property of diamond coatings on WC–10%Co substrates. Prior to diamond deposition, an interlayer of 1.5 μm thick Cr–N was deposited on the WC–Co substrates to minimize diffusion of cobalt and also to relax the interfacial residual stresses to some extent. Diamond films were deposited using hot filament chemical vapor deposition technique at different temperatures (500–750 °C). Improved adhesion was found for diamond films deposited at 650 °C, compared to the films deposited at other temperatures. Our analysis, showed that thickness of the Cr-C interlayer formed at the interface is dependent on the substrate temperature, which in turn influence the adhesion strength. A comprehensive analysis about the optimum deposition temperature that leads to better adhesion is discussed. In addition, it was found that Cr-N surface morphology also plays an important role in determining the performance of diamond films by mechanical interlocking.