CHEMICAL VAPOR-DEPOSITION DIAMOND COATINGS ON CEMENTED CARBIDE TOOLS

Low-pressure synthesis of diamond offers the possibility of forming in situ diamond coatings which can significantly increase the technical performance of cutting devices. One problem of diamond deposition onto cemented carbide tools is the presence of cobalt on the tool surface which can disturb diamond nucleation and growth, thus leading to poor adhesion. In this work, by applying etching and low-temperature deposition conditions, optimal diamond deposition and excellent adhesion were produced. The surface preparation of the inserts, the deposition method (hot filament), a simple characterization test for the coatings, and industrial cutting tests are discussed. Limited numbers of cutting tests showed the quality of the diamond layers and their adhesion in comparison with conventional polycrystalline diamond tools. The results showed that the performance of low-pressure diamond coatings, at least for turning tests of short duration, can reach the level of polycrystalline diamond.