Adhesion of diamond film on functionally gradient WC-10wt. %Co hardmetal

Diamond coated tools of cemented carbide substrate with high Co content are extremely useful for machining difficult-to-cut materials. However, it is very difficult to deposit a well-adherent diamond coating on WC-Co with high Co content because of the strong catalytic effect of Co. In this work, a new functionally gradient WC-10wt. %Co hardmetal not containing. phase with a Co-depleted surface layer was fabricated. Diamond film was deposited on the gradient WC-10 wt. %Co by the hot filament chemical vapor deposition technique, and the quality and adhesion of diamond film were evaluated. The results indicate that the functionally gradient WC-10 wt. %Co hardmetal shows high adhesion strength to the diamond coating, and is a very promising substrate material for producing diamond coated tools.