TY - JOUR A1 - Österle, Werner A1 - Bettge, Dirk A1 - Fedelich, Bernard A1 - Klingelhöffer, Hellmuth T1 - Modelling the orientation and direction dependence of the critical resolved shear stress of nickel-base superalloy single crystals PY - 2000 SN - 1359-6454 SN - 1873-2453 VL - 48 SP - 689 EP - 700 PB - Elsevier Science CY - Kidlington AN - OPUS4-2366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schempp, Philipp A1 - Cross, C.E. A1 - Pittner, Andreas A1 - Oder, Gabriele A1 - Neumann, R. S. A1 - Rooch, Heidemarie A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Rethmeier, Michael T1 - Solidification of GTA aluminium weld metal: Part I - Grain morphology dependent upon alloy composition and grain refiner content N2 - The solidification conditions during welding strongly influence the weid metal microstructure and mechanical properties of a weid. In the first part of this study, the grain morphology of gas tungsten arc (GTA) bead-on-plate welds was investigated for the aluminum Alloys 1050A (Al 99.5), 6082 (Al SifMgMn), and 5083 (AI Mg4.5Mn0.7). The experiments revealed that increasing welding speed and alloy content allow the growth of small, equiaxed grains, particularly in the weid center. Furthermore, increasing grain refiner additions led to a Strong reduction of the weid metal mean grain size and hence facilitated the columnar to equiaxed transition (CET). In addition, wavelength dispersive X-ray spectroscopy (WDS) and transmission electron microscopy (TEM) analysis revealed in the weid metal TiB2 particles that were surrounded by Al3Ti. This suggests the duplex nucleation theory for nucleation of aluminum grains in GTA weid metal. KW - Aluminium KW - Gas tungsten arc welding (GTAW) KW - Grain refinement KW - Columnar to equiaxed transition (CET) KW - Epitaxial nucleation KW - Duplex nucleation theory PY - 2014 SN - 0043-2296 SN - 0096-7629 VL - 93 SP - 53-s EP - 59-s PB - American Welding Society CY - New York, NY AN - OPUS4-30413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Österle, Werner A1 - Deutsch, Cornelius A1 - Rooch, Heidemarie A1 - Dörfel, Ilona T1 - Friction films on C-SiC discs after dynamometer tests with different commercial brake pads N2 - Brake discs on the basis of carbon fibre reinforced SiC-ceramics are appreciated as a light weight high performance alternative to conventional cast iron brake discs. Although efforts are going on to develop ceramic pads of a similar material but with additions of friction modifiers, comfort requirements cannot be reached with a full ceramic system and therefore commercial solutions still are based on polymer matrix composites (PMCs) and in some rare cases on sinter metallic (SM) friction materials. In previous studies with conventional automotive brakes an iron oxide based friction film on the surfaces of pads and discs was observed. This seemed to be plausible since iron is the major element of the cast iron disc and furthermore is contained in most pad formulations in the form of steel fibres. Therefore it was of great scientific interest to determine the relevance and composition of friction films on ceramic brake discs which do not contain any iron. T2 - EuroBrake 2012 CY - Dresden, Germany DA - 16.04.2012 KW - Ceramic disc KW - Friction film KW - PMC-pad KW - SM-pad KW - Third body PY - 2012 IS - EB2012-FM-01 SP - 1 EP - 9 AN - OPUS4-26823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Merk, Virginia A1 - Schulte, Franziska A1 - Rooch, Heidemarie A1 - Feldmann, Ines A1 - Dörfel, Ilona A1 - Österle, Werner A1 - Panne, Ulrich A1 - Kneipp, Janina T1 - Surface-enhanced Raman scattering with silver nanostructures generated in situ in a sporopollenin biopolymer matrix N2 - Silver nanoparticles were generated based on citrate reduction in the ultrastructure of the sporopollenin biopolymer of Ambrosia artemisiifolia (ragweed) and Secale cereale (rye). The nanoparticles enable the acquisition of SERS spectra and thereby a vibrational characterization of the local molecular structure of sporopollenin. PY - 2011 DO - https://doi.org/10.1039/c0cc05326k SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x N1 - Geburtsname von Merk, Virginia: Joseph, V. - Birth name of Merk, Virginia: Joseph, V. VL - 47 IS - 11 SP - 3236 EP - 3238 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-23482 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Senoner, Mathias A1 - Maaßdorf, A. A1 - Rooch, Heidemarie A1 - Österle, Werner A1 - Malcher, M. A1 - Schmidt, M. A1 - Kollmer, F. A1 - Paul, D. A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Unger, Wolfgang T1 - Lateral resolution of nanoscaled images delivered by surface-analytical instruments: application of the BAM-L200 certified reference material and related ISO standards N2 - The certified reference material BAM-L200, a nanoscale stripe pattern for length calibration and specification of lateral resolution, is described. BAM-L200 is prepared from a cross-sectioned epitaxially grown layer stack of AlxGa1–xAs and InxGa1–xAs on a GaAs substrate. The surface of BAM-L200 provides a flat pattern with stripe widths ranging down to 1 nm. Calibration distances, grating periods and stripe widths have been certified by TEM with traceability to the length unit. The combination of gratings, isolated narrow stripes and sharp edges of wide stripes offers plenty of options for the determination of lateral resolution, sharpness and calibration of length scale at selected settings of imaging surface-analytical instruments. The feasibility of the reference material for an analysis of the lateral resolution is demonstrated in detail by evaluation of ToF-SIMS, AES and EDX images. Other applications developed in the community are summarized, too. BAM-L200 fully supports the implementation of the revised International Standard ISO 18516 (in preparation) which is based on knowledge outlined in the Technical Report ISO/TR 19319:2013. KW - AES KW - BAM-L200 KW - CRM KW - EDX KW - Imaging KW - Lateral resolution KW - Sharpness KW - Standardisation KW - STXM KW - ToF-SIMS KW - XPEEM KW - XPS KW - Certified reference material KW - Imaging surface analysis PY - 2015 DO - https://doi.org/10.1007/s00216-014-8135-7 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 11 SP - 3211 EP - 3217 PB - Springer CY - Berlin AN - OPUS4-33033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ortel, Erik A1 - Häusler, Ines A1 - Österle, Werner A1 - Narbey, S. A1 - Oswald, F. A1 - Andersen, I. H. A1 - Holzweber, Markus A1 - Unger, Wolfgang A1 - Hodoroaba, Vasile-Dan T1 - In-depth structural and chemical characterization of engineered TiO2 films N2 - Analytical routines for a comprehensive in-depth morphological, structural, and chemical characterization of functionalized TiO2 films by using different state-of-the-art analytical techniques are presented and discussed with the main objective to identify potential reference TiO2 coating parameters able to be certified at a later stage. TiO2 films fabricated by two different synthetic procedures as representative for two main large-scale applications were selected: (i) pulsed d.c. magnetron sputtering for photocatalytic applications and (ii) screen printing from preformed anatase nanoparticles. The screen-printed films were further loaded with a sensitizing dye for application as a dye-sensitized solar cell. Film properties such as microstructure and crystallographic texture of pulsed d.c. magnetron sputtering synthesized films were systematically studied by means of scanning nanobeam electron diffraction in a transmission electron microscope and the surface and inner morphology by scanning electron microscopy. The dye distribution over the depth of screen-printed TiO2 layers was analyzed before and after dye-loading by means of energy dispersive X-ray spectroscopy at scanning electronmicroscope, Auger electron spectroscopy and time-of-flight secondary ion mass spectrometry. The long-term goal of the present study is the improvement of quality of the TiO2 film parameters as measured by using different types of reference TiO2 coatings having specific parameters certified. T2 - 16th European Conference on Applications of Surface and Interface Analysis ECASIA'15 CY - Granada, Spain DA - 28.09.2015 KW - Mapping KW - Line scan KW - Depth profiling KW - TiO2 films KW - Crystallinity KW - Ru dye sensitizer PY - 2016 DO - https://doi.org/10.1002/sia.5966 SN - 0142-2421 SN - 1096-9918 VL - 48 SP - 664 EP - 669 PB - John Wiley & Sons, Ltd. AN - OPUS4-36791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grulke, E. A. A1 - Yamamoto, K. A1 - Kumagai, K. A1 - Häusler, Ines A1 - Österle, Werner A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Brown, S. C. A1 - Chan, C. A1 - Zheng, J. A1 - Yamamoto, K. A1 - Yashiki, K. A1 - Song, N. W. A1 - Kim, Y. H. A1 - Stefaniak, A. B. A1 - Schwegler-Berry, D. A1 - Coleman, V. A. A1 - Jämting, Å. K. A1 - Herrmann, J. A1 - Arakawa, T. A1 - Burchett, W. W. A1 - Lambert, J. W. A1 - Stromberg, A. J. T1 - Size and shape distributions of primary crystallites in titania aggregates N2 - The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions were multi-modal but data visualization plots demonstrated that the Weibull distribution was preferred to the normal distribution. For the equivalent circular diameter size descriptor, measurement uncertainties of the lognormal distribution scale and width parameters were 9.5% and 22%, respectively. For the aspect ratio shape descriptor, the measurement uncertainties of the Weibull distribution scale and width parameters were 7.0% and 26%, respectively. Both measurement uncertainty estimates and data visualizations should be used to analyze size and shape distributions of particles on the nanoscale. KW - Measurement uncertainty KW - Size distribution KW - Shape distribution KW - TEM KW - Titania PY - 2017 DO - https://doi.org/10.1016/j.apt.2017.03.027 SN - 0921-8831 VL - 28 IS - 7 SP - 1647 EP - 1659 PB - Elsevier B.V. AN - OPUS4-40478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dmitriev, A.I. A1 - Kloß, Heinz T1 - Possible impacts of third body nanostructure on friction performance during dry sliding determined by computer simulation based on the method of movable cellular automata N2 - The tribological properties of nanostructured surface films formed during dry sliding, for example during automotive braking, were determined by modelling using the method of movable cellular automata. Starting from a basic model structure, consisting of magnetite with 13% graphite inclusions, the impact of additional soft and hard particles of different size and volume fraction was studied systematically. It was revealed that agglomerates of soft particles decomposed and finally mixed with the oxide in the same way as single nanoparticles. On the other hand, agglomerates of hard particles mixed with the other components without decomposing. Whereas increasing the amount of soft components in the third Body lowered the coefficient of friction, the opposite occurred with the hard particles. The boundary conditions for obtaining smooth sliding conditions with minor fluctuations between friction forces at successive time steps could be defined. In addition to features of the nanostructure, the applied normal pressure impacted modelling results. Within the parameter range of smooth sliding behaviour, increasing pressure induced thicker granular interface layers, which lead to a slight decrease of the coefficient of friction. Changing the amount of soft or hard particles did not change this pressure dependency but only the friction level. KW - MCA-modelling KW - Third body KW - Nanoparticles KW - Dry friction PY - 2012 DO - https://doi.org/10.1016/j.triboint.2011.11.018 SN - 0301-679X VL - 48 SP - 128 EP - 136 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-25469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Natte, Kishore A1 - Behnke, Thomas A1 - Orts Gil, Guillermo A1 - Würth, Christian A1 - Friedrich, Jörg Florian A1 - Österle, Werner A1 - Resch-Genger, Ute T1 - Synthesis and characterisation of highly fluorescent core-shell nanoparticles based on Alexa dyes N2 - Current and future developments in the emerging field of nanobiotechnology are closely linked to the rational design of novel fluorescent nanomaterials, e.g. for biosensing and imaging applications. Here, the synthesis of bright near infrared (NIR)-emissive nanoparticles based on the grafting of silica nanoparticles (SNPs) with 3-aminopropyl triethoxysilane (APTES) followed by covalent attachment of Alexa dyes and their subsequent shielding by an additional silica shell are presented. These nanoparticles were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. TEM studies revealed the monodispersity of the initially prepared and fluorophorelabelled silica particles and the subsequent formation of raspberry-like structures after addition of a silica precursor.Measurements of absolute fluorescence Quantum yields of these scattering particle suspensions with an integrating sphere setup demonstrated the influence of dye labelling density-dependent fluorophore Aggregation on the signaling behaviour of such nanoparticles. KW - Silica KW - Alexa dyes KW - Fluorescent particles KW - Quantum yields KW - Nanoparticles KW - Protective shell KW - Nanobiotechnology PY - 2012 DO - https://doi.org/10.1007/s11051-011-0680-9 SN - 1388-0764 SN - 1572-896X VL - 14 IS - 2 SP - 680-1 - 680-10 PB - Kluwer CY - Dordrecht AN - OPUS4-25872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dmitriev, A.I. A1 - Nikonov, A.Y. A1 - Österle, Werner T1 - Multiscale modeling of low friction sliding behavior of a hybrid epoxy-matrix nanocomposite N2 - The method of movable cellular automata (MCA) and method of molecular dynamics (MD) were applied to simulate the friction and sliding behavior of model-tribofilms formed from a nanocomposite consisting of an epoxy matrix, 10 vol % micron-sized carbon fibers and 5 vol. % silica nanoparticles. Whereas MCA considered the tribofilm as an agglomerate of silica nanoparticles released from the composite and mixed with graphite particles, MD simulated the sliding behavior of an amorphous silica layer supported by stiff crystalline substrates on both sides. The MCA model provided reasonable quantitative results which corroborate experimental findings at moderate stressing conditions. The very low coefficient of friction observed experimentally under severe stressing conditions was not explained by this model. This could be attributed to the lack of mechanical data at the high temperature expected under these conditions. Although based on a simpler assumption of the tribofilm composition, MD-modelling could be easily applied to the expected high flash temperature and was able to predict friction reduction and smooth sliding under these conditions. T2 - 21st European Conference on Fracture ECF21 CY - Catania, Italy DA - 20.06.2016 KW - Silica nanoparticle KW - Hybrid composite KW - Tribofilm KW - Molecular dynamics KW - Movable cellular automata PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379402 DO - https://doi.org/10.1016/j.prostr.2016.06.294 VL - 2 SP - 2347 EP - 2354 PB - Elsevier Ltd. AN - OPUS4-37940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Orts Gil, Guillermo A1 - Natte, Kishore A1 - Österle, Werner T1 - Multi-parametric reference nanomaterials for toxicology: state of the art, future challenges and potential candidates N2 - A major requirement for the validation of methods assessing the risk associated with engineered nanoparticles (ENPs) is the use of reference materials (RMs). In the present contribution we review available RMs, ongoing projects and characterisation trends in the field. The conclusion is that actual approaches to RMs mostly deal with metrological considerations about single properties of the ENPs, typically their primary size, which can hardly be representative of nanoparticles characteristics in real testing media and therefore, not valid for reliable and comparable toxicological studies. As an alternative, we discussed the convenience and feasibility of establishing multi-parametric RMs for a series of ENPs, focusing on silica nanoparticles (SNPs). As a future perspective, the need to develop RMs based on hybrid nanoparticles is also discussed. KW - Referenzmaterialien KW - Nanopartikel KW - Toxikologie KW - Metrologie PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-292997 DO - https://doi.org/10.1039/c3ra42112k SN - 2046-2069 VL - 3 IS - 40 SP - 18202 EP - 18215 PB - RSC Publishing CY - London AN - OPUS4-29299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Engelhardt, Monika A1 - Gesatzke, Wolfgang A1 - Österle, Werner A1 - Müller, Urs A1 - Rooch, Heidemarie A1 - Saliwan Neumann, Romeo A1 - Urban, Ingrid T1 - Makro- und Mikrogefüge von Bremsbelägen KW - Bremsbelag KW - Polymermatrix-Verbundstoff KW - Röntgenfluoreszenzanalyse KW - REM KW - FIB KW - TEM PY - 2005 SN - 3-88355-343-3 SN - 0343-3579 N1 - Serientitel: Sonderbände der praktischen Metallographie – Series title: Sonderbände der praktischen Metallographie IS - 37 SP - 105 EP - 110 PB - Werkstoff-Informationsges. CY - Frankfurt AN - OPUS4-10996 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dmitriev, A. I. A1 - Österle, Werner ED - Österle, Werner ED - Zhang, G. T1 - The role of solid lubricants for brake friction materials N2 - This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol.% of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and a minimum of wear. KW - Solid lubricant KW - Friction KW - Automotive braking KW - Tribofilm KW - Sliding simulation KW - MCA-modeling PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355973 UR - www.mdpi.com/journal/lubricants DO - https://doi.org/10.3390/lubricants4010005 SN - 2075-4442 VL - 4 IS - 1 SP - 5 EP - 26 PB - MDPI CY - Basel, Switzerland AN - OPUS4-35597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wollschläger, Nicole A1 - Tasdemir, Z. A1 - Häusler, Ines A1 - Leblebici, Y. A1 - Österle, Werner A1 - Alaca, B. E. T1 - Determination of the elastic behavior of silicon nanowires within a scanning electron microscope N2 - Three-point bending tests were performed on double-anchored, <110> silicon nanowire samples inside a scanning electron microscope (SEM) via a micromanipulator equipped with a piezo-resistive force sensor. Representing the upper and lower boundaries achievable in a consistent manner, silicon nanowires with widths of 35 nm and 74 nm and a height of 168 nm were fabricated. The nanowires were obtained monolithically along with their 10-m-tall supports through a top-down fabrication approach involving a series of etching processes. Hence, no interface compliance was introduced between supports and nanowires. Exact nanowire dimensions and cross-sectional features were determined by transmission electron microscopy (TEM) following sample preparation through focused ion beam (FIB) machining. Conducting the experiments inside an SEM chamber further raised the opportunity of the direct observation of any deviation from ideal loading conditions such as twisting, which was taken into consideration in simulations. Measured force-displacement behavior was observed to exhibit close resemblance to simulation results obtained by finite element modeling, when the bulk value of 169 GPa was taken as the modulus of elasticity for <110> silicon. Hence, test results show neither any size effect nor evidence of residual stresses for the considered nanoscale objects. The increased effect of the native oxide with reduced nanowire dimensions was captured as well. Thus this very simple in-situ testing method was found to be an alternative to elaborate AFM measurements on geometrically formidable nanostructures. The results demonstrate the applicability of the developed fabrication approach to the incorporation of silicon nanowires in functional micromechanical devices. KW - Silicon nanowire KW - Elastic behavior KW - Scanning electron microscope KW - Mechanical properties PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370383 DO - https://doi.org/10.1155/2016/4905838 VL - 2016 SP - Article 4905838, 1 EP - 6 PB - Hindawi Publishing Corporation AN - OPUS4-37038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Nikonov, A. Y. A1 - Dmitriev, A. I. ED - Krzanowski, J. T1 - MD sliding simulations of amorphous tribofilms consisting of either SiO2 or carbon N2 - The sliding behaviors of two simplified tribofilms with amorphous structure consisting either of SiO₂ molecules or C atoms were simulated by molecular dynamics modeling. The objective was to identify mechanisms explaining the experimentally observed lubricating properties of the two amorphous films. The impacts of layer thickness, normal pressure, temperature and different substrate materials were studied systematically, while the sliding velocity was kept constant at 30 m/s. While the layer thickness was not critical, all the other parameters showed special effects under certain conditions. Normal pressure impeded void formation and could even eliminate voids if applied at high temperature. Stick-slip sliding was changed to smooth sliding at high temperature due to void healing. Considering the carbon film, high friction forces and shearing of the entire film was observed with diamond substrates, whereas interface sliding at low friction forces and an amorphous layer of iron mixed with carbon was observed if the supporting substrates consisted of α-Fe. Both films show a decrease of friction forces and smooth sliding behavior at elevated temperature, corresponding well to the tribological behavior of and advanced nanocomposite sliding against a steel disc under severe stressing conditions when high flash temperatures can be expected. KW - dry friction KW - amorphous silica film KW - amorphous carbon film KW - sliding simulation KW - molecular dynamics PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379367 DO - https://doi.org/10.3390/lubricants4030024 VL - 4 IS - 24 PB - MDPI CY - Basel, Switzerland AN - OPUS4-37936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Österle, Werner A1 - Brückner, A. A1 - Weihnacht, V. T1 - Friction and endurance of MoS2/ta-C coatings produced by laser arc deposition N2 - The tribological behaviour of MoS2/ta-C double layer coatings deposited by Laser-Arc technology was investigated in vacuum and air. In vacuum environment, the friction coefficient against steel balls varies between 0.005 and 0.02 depending on the contact pressure. At high contact pressures, the friction coefficient is as low as 0.005 and the life time between 340,000 and 500,000 cycles. Furthermore, it is shown that a ta-C base layer improves the performance of MoS2 coating. Surface analyses were performed before and after the tribological tests by means of SEM, EDX, XRD, and TEM. They show that in the top layer beneath the sliding surface crystallization of the initially quasi-amorphous MoS2 took place. TEM images also verified an orientation of the basal MoS2-lattice planes parallel to the surface. KW - MoS2 coatings KW - Ta-C KW - Vacuum KW - Laser arc deposition PY - 2013 DO - https://doi.org/10.1016/j.wear.2012.10.007 SN - 0043-1648 VL - 297 IS - 1-2 SP - 791 EP - 801 PB - Elsevier CY - Amsterdam AN - OPUS4-27114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -