Mechanical pretreatment for improved adhesion of diamond coatings

Diamond coatings are mainly used in cutting processes due to their tribolog ical characteristics. They show a high hardness, low friction coefficient, high wear resistance and good chemical inertness. In relation to polycrysta lline diamond (PCD)-tipped cutting inserts, especially the advantageous che mical stability of diamond coatings is superior as no binder phases between diamond grains are used. However, the deposition of adherent high-quality diamond coatings has been found difficult. Thus, substrate pretreatment is utilised to improve film adhesion. This investigation is based on water pee ning of the substrate material before coating. The investigation revealed b est results for diamond film adhesion on pretreated substrates compared to conventional diamond coatings on cemented carbide tools applied with the CV D hot-filament process. In final cutting tests with increased film adhesion trough water peened cutting tools an improved wear behavior was detected. (C) 1999 Elsevier Science S.A. All rights reserved.