Abstract. The main aim of the studies was the deposition of the AlCrN film, covered by molybdenum disulphide (MoS2) -based lubricant, on the austenitic steel substrate. The AlCrN and MoS2 layers were deposited by PVD lateral rotating ARC-cathodes (LARC) and magnetron sputtering technology on the X6CrNiMoTi17-12-2 respectively. Structural characterizations of the MoS2 thin films have been carried out using SEM (scanning electron microscopy) and AFM (atomic force microscopy) to determine the surface topography as well as HRTEM (high-resolution transmission electron microscopy) and Raman spectroscopy for structural investigations. The tribological wear relationships using ball-on-disc test were specified for surface layers, determining the friction co-efficient and mass loss of the investigated surfaces. Tests of the coatings' adhesion to the substrate material were made using the scratch test. HRTEM investigation shows an amorphous character of the MoS2 layer. In sliding dry friction conditions, the friction co-efficient for the investigated elements is set in the range between 0.4-0.5. The investigated coating reveals high wear resistance. The coating demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate. The good properties of the PVD AlCrN+MoS2 coatings make them suitable in various engineering and industrial applications.

Deposited on hot work tool steel substrate coating system composed of AlTiCrN film covered by diamond-like carbon (DLC)-based lubricant, was the subject of the studies. The AlTiCrN and DLC layers were deposited by PVD lateral rotating ARC-cathodes (LARC) and PACVD technology on the X40CrMoV5-1 respectively. This paper provides an analysis of the microstructure, mechanical and tribological properties. Several surface sensitive techniques and methods, i.e. High Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Raman spectroscopy and ball-on-disk were used to performed study of the coating. TEM investigation shows an amorphous character of DLC layer. It was found that tested AlTiCrN layer has nanostructural character with fine crystallites. In sliding dry friction conditions the friction coefficient for the investigated elements is set in the range between 0.02-0.04. The investigated coating reveals high wear resistance. The coating demonstrated good adhesion to the substrate.

Purpose: The purpose of this article is to characterize and compare the microstructure and tribological properties of low friction DLC:Ti and MoS2 thin films deposited on the austenitic steel X6CrNiMoTi17-12-2 substrate. Design/methodology/approach: In the research, the samples of the DLC:Ti and MoS2 thin films deposited by PACVD technology and magnetron sputtering method respectively were used. Observations of topography were made using atomic force microscope (AFM). Adhesion of the coating to the substrate material was verified by the scratch test. The friction coefficient and wear rate of the coating were determined in the ball-on-disc test. Findings: AFM as well as adhesion and friction coefficient tests confirmed low friction nature of MoS2 and DLC:Ti coatings. During the research information on the behaviour of coatings under tribological load was obtained. The investigated coating reveals high wear resistance and good adhesion to the substrate. Practical implications: The area of testing of low-friction thin films is widely studied due to their practical application. Intensive development of new technologies requires the introduction of corresponding layers of both full protective functions and reducing friction. Originality/value: Growing area of low-friction coatings with specific properties requires thorough tribological and topographical research, which is closely related to these properties.

The paper presents results of the investigation of the AlCrN and AlCrN + CrCN coatings, deposited by arc evaporation method on the austenitic steel substrate. Topography studies performed with the use of AFM showed that the roughness value was 24 nm for AlCrN and 14 nm for CrCN. Chemical analysis carried out with energy dispersive X-rays spectroscopy confirmed the chemical composition of the coatings. Transmission electron microscopy (TEM) investigations showed a column structure of AlCrN and CrCN layers with a width in the range of 10–200 nm. Tribological properties analyzed using a scratch test and ball-on-disc method showed a good adhesion of the coatings to the substrate (LC2 is 40 and 46 N for AlCrN and AlCrN + CrCN, respectively) and its high wear resistance; the use of an additional CrCN layers caused a decrease in the friction coefficient by 19%. Structure modification of the AlCrN + CrCN coating system and the related improvement in its mechanical and tribological properties allowed increasing the lifetime of the coated elements. The original approach was to produce a dual-layer coating, consisting of an internal, hard AlCrN layer and an external layer of CrCN, providing good tribological properties, as well as an appropriate forming of the transition zone between the layers.

Low friction thin layers are an excellent alternative for conventional coatings. They provide increased life of the elements, to which they were applied, due to enhancing the hardness or chemical and electrochemical resistance. They help to avoid the cracks, oxidation, as well as possible structural changes during the element's work. However, they primarily improve tribological properties by increasing wear resistance and reducing the friction. This also applies to components operating under variable conditions such as load, speed, temperature. The presented article analyzes the properties of various low-friction thin layers deposited by vacuum methods on the steel substrates. DLC, TiC, MoS2, CrCN thin layers were chosen, as they achieve the lowest possible coefficient of friction. In the framework of this work the measurements of adhesion of the investigated layers to the substrate as well as the friction coefficient, chemical analysis, microstructure and topographic analysis of the low-friction layers were carried out.