In magnetron sputtering the material is sputtered from a target and deposited on the areas of substrates that are in the line-of-sight of the vaporization source. In industrial deposition systems the substrates are normally fixed on a turntable, which performs a planetary-type of rotation. In this work, our previously developed simulation of coating growth in an industrial deposition system with a planetary type of rotation has been used to analyze the influence of the rotation and target arrangement on the uniformity and periodicity of layered coatings. Results of simulations show that highly periodic modes of rotation, which are determined by the turntable gear ratio and the switch angle, cause large non-uniformities both in the thickness and the composition of layered coatings. On the other hand, less periodic modes of rotation produce better coating uniformity although for certain rotation parameters significant non-uniformities may also occur. The simulation has attracted interest of researchers and several companies, and resulted in signing a research contract with one of the largest manufacturers of PVD systems for deposition of hard coatings.
COBISS.SI-ID: 26959655
In order to increase machinability, cutting tools are widely coated with nanostructured PVD hard coatings. The main characteristics of such advanced hard coatings are high microhardness and toughness as well as good adhesion to the substrate. In this paper, the influence of hard coatings (blue nanolayer AlTiN/TiN, multilayer nanocomposite TiAlSiN/TiSiN/TiAlN, and for comparison commercially available TiN/TiAlN) and cutting parameters (cutting speed, feed rate, and depth of cut) on cutting forces and surface roughness od workpiece were investigated during face milling of AISI O2 cold work tool steel (∼61 HRC). The effect of the main cutting parameters on cutting force and surface roughness was examined using full factorial design and analysis of variance (ANOVA). In addition, the cutting forces obtained with the coated and uncoated tools were compared. The results showed that the interaction of coating type and depth of cut affects surface roughness of workpiece. The hard coating type has no significant effect on cutting forces, while the cutting force Fz is approximately two times higher in the case of uncoated tool.
COBISS.SI-ID: 26698279
Reduction of wear and corrosion, along with increasing thermal stability of tools and mechanical components present industrial challenges which demand continuous development of new coating materials and coating design concepts. Recently, the main attention has been placed on research and application of nanolayer and nanocomposite hard coatings. In this study, TiAlN and TiSiN layers where alternatively deposited to produce a nanolayered nanocomposite TiAlSiN coating. Single-layer TiAlN and TiSiN coatings were deposited along with the nanolayered coating for better understanding of its properties. All coatings were prepared by sputtering in an industrial unit equipped with four unbalanced magnetron sources (two TiAl and two TiSi). Coating microstructure was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Chemical composition were determined by X-ray photoelectron spectroscopy (XPS). Mechanical properties were measured by nanoindentation technique. According to XRD and XPS measurements, nanolayered TiAlSiN coating consists of crystalline fcc-TiN like and amorphous Si3N4 phases. TEM analysis revealed that TiSiN layers block the growth of TiAlN crystallites which are equiaxed and size around 5 nm. As a result, TiAlSiN coating exhibit high hardness (39 GPa) which is attributed to limited dislocation activity in small crystals and suppression of grain boundary sliding.
COBISS.SI-ID: 27291943