SURFACE MODIFICATION OF CEMENTED CARBIDE CUTTING TOOLS FOR IMPROVED ADHESION OF DIAMOND COATINGS

Diamond coatings are mainly used in cutting processes due to their tri bological characteristics. They show a high hardness, a low friction c oefficient, high wear resistance and a good chemical inertness. In rel ation to polycrystalline diamond (PCD)-tipped cutting inserts especial ly the advantageous chemical stability of diamond coatings is superior as no binder phases between diamond grains are used. However, the dep osition of adherent high quality diamond coatings has been found diffi cult. Thus, substrate pretreatment is utilized to improve film adhesio n. This investigation is based on water peening of the substrate mater ial before coating. The investigation revealed best results for diamon d film adhesion on pretreated substrates compared to conventional diam ond coatings on cemented carbide tools applied with the CVD hot-filame nt process. In final cutting tests with increased film adhesion water- peened cutting tools an improved wear behavior was detected. (C) 1998 Elsevier Science S.A. All rights reserved.