Investigation studies involving wear-resistant ALD/PVD hybrid coatings on sintered tool substrates

This paper is an important research contribution to the development of PVD coatings, in particular, on ceramic substrates, which, due to their dielectric properties, are difficult materials to coat using this technique.In order to satisfy the desired expectations relating to the PVD coatings, one of the basic properties must be provided for, the adherence to the substrate.The main aim of this research is to investigate the structure and mechanical properties of the coatings deposited in a hybrid process, comprising the atomic-layer deposition (ALD) and cathodic-arc evaporation (CAE-PVD) on sintered carbides and multipoint ceramic cutting tools.The concept of this research study involves an execution and investigation of ALD + PVD hybrid coatings on sintered carbides and a sialon-ceramic substrate, and defining the influence of the ALD interlayer on the adherence of the investigated coatings.The critical load Lc, which is the adhesion measure of coats, was determined with the scratch-test method and a tribological test made with a pin-on-disk tester.Observations of the surface topography and wear mechanism were performed using a scanning electron microscope and atomic-force microscopy.The investigation studies showed that an ALD layer considerably improves the adherence of the PVD layer to the tool-ceramic substrate.The research of the coatings on sintered-carbide substrates showed that the adherence of the PVD coating to the substrate deteriorates in the case of applying an ALD interlayer.