Effect of depositing the hard surface coatings on properties of the selected cemented carbides and tool cermets

The paper presents results of the structural examinations, tests of mechanical and working properties of thin anti-wear coatings of the TiN/TiAlSiN/TiN type, deposited in the PVD process onto the substrate from the tool cermets and sintered carbides. Structural examinations are presented of the applied coatings and their substrate made on the scanning electron microscope and on the light microscope. Evaluation of the adhesion of the deposited coatings onto the sintered carbides and cermets was made using the scratch test. The lowest force L_C called the critical load was determined based on the acoustic emission value (AE), at which loss of the coating adhesion to the substrate occurs. Cutting properties of the investigated materials were determined based on the technological continuous cutting tests of the C45E steel. Width of the wear band on the tool flank VB_max = 0.2 mm was assumed as the cutting edge wear criterion for finishing. Substrate hardness tests and micro-hardness tests of the deposited coatings were made on the ultra-micro-hardness tester at 70 mN load. Surface roughness tests were also made before depositing the coatings and after completing the PVD process.