TY - JOUR A1 - Cappella, Brunero A1 - Hartelt, Manfred A1 - Wäsche, Rolf T1 - High resolution imaging of macroscopic wear scars in the initial stage N2 - The topography of wear scars on the surface of a steel disc coated with a diamond-like carbon (DLC) layer has been investigated with an Atomic Force Microscope (AFM). AFM topography images have been combined together taking advantage of the stitching technique for the study of wear scars in their initial stage. Moreover, the topography of the sample has been acquired before and after the sliding tests. In this way even very small changes of the sample surface (<10 nm) can be detected. Three main phenomena taking place at the very initial stage of wear could be identified: the abrasion of small asperities bulging out of the sample surface, the carving of swallow grooves with depth under 20 nm, and the partial or total closure of cavities present on the surface. This last phenomenon shows that, before the carving of a wear scar, the plastic deformation of particular regions of the sample, i.e. the volume around the cavities, takes place already after few cycles (in this case between 400 and 800) in the initial phase of the sliding test. KW - Atomic force microscopy KW - Stitching technique KW - Running in KW - Plastic deformation PY - 2015 DO - https://doi.org/10.1016/j.wear.2015.07.013 SN - 0043-1648 VL - 338-339 SP - 372 EP - 378 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-34734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Hartelt, Manfred A1 - Cappella, Brunero T1 - The use of AFM for high resolution imaging of macroscopic wear scars N2 - In this article we demonstrate the use of atomic force microscopy (AFM) measurements for the study of macroscopic wear scars. By stitching AFM images acquired over the wear scar, the detailed structure of the scar can be characterized even when the scar is much wider than the typical maximum scan range of the AFM (50–100 µm). The results obtained by AFM are compared with those yielded by white light interferometry (WLI). The comparison validates the WLI measurements; at the same time, it shows decisive differences in the resolutions of these two methods. As a consequence, AFM measurements are necessary whenever a precise characterization of the structure of the scar is required. However, since stitching of AFM images is rather time-consuming, white light interferometry is recommended as a faster method whenever experiments are aimed at just a gross characterization of the scar and the measurement of mean quantities (e.g. the wear volume). KW - Wear scar KW - Imaging KW - Roughness KW - Wear volume KW - Atomic force microscopy KW - White light interferometry PY - 2014 DO - https://doi.org/10.1016/j.wear.2013.11.009 SN - 0043-1648 VL - 309 IS - 1-2 SP - 120 EP - 125 PB - Elsevier CY - Amsterdam AN - OPUS4-30289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harsha, A.P. A1 - Wäsche, Rolf A1 - Hartelt, Manfred T1 - Tribological studies on polyetherketone composite under reciprocating sliding condition against steel cylinder N2 - Tribological studies on neat polyetherketone (PEK) and glass fiber reinforced PEK composite were carried out at room and elevated temperature (120 °C). The objective of this study was to characterize for friction and wear properties under dry reciprocating sliding condition at different experimental conditions. The polymer specimens were made to oscillate against steel cylinder as a counterpart. This kind of contact condition are frequently found in bushes, sliding bearing, electronic parts, seals, etc. The friction and wear behavior of neat PEK and composite was quite different at room temperature and elevated temperature. It was observed that glass fiber reinforcement is beneficial in controlling the wear of PEK matrix at room temperature than at elevated temperature. The test results are discussed by considering the surface properties i.e. material removal and film transfer formation. Scanning electron micrographs and optical micrographs of the worn polymer and steel cylinder was used to study the wear mechanisms. KW - Dry oscillating sliding KW - Polyetherketone composite KW - Wear mechanism KW - Contact geometry PY - 2015 DO - https://doi.org/10.1177/1350650115570403 SN - 1350-6501 VL - 229 IS - 7 SP - 795 EP - 806 PB - Institution of Mechanical Engineers CY - London AN - OPUS4-33526 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Yarim, Rasim A1 - Klaffke, Dieter A1 - Hartelt, Manfred T1 - Oscillating sliding wear behaviour of SiC, TiC, TiB2, 59SiC-41TiB2 and 52SiC-24TiC-24TiB2 materials up to 750°C in air N2 - The tribological behaviour of different monolithic and composite ceramics was evaluated in the temperature range between room temperature and 750°C. The test method was oscillating sliding with a ball-on-disk arrangement in an SRV machine. Alumina balls were used as counter body. The friction behaviour was determined on-line, and the wear behaviour was determined from calculations on the basis of wear scar dimensions and profilometric measurements. The friction depends on temperature and shows an increase for most materials for increasing temperature; the smallest friction at all temperatures is found for monolithic TiC. The wear behaviour shows different trends for the different materials. In tests against SiC a maximum of wear is found at 500°C, for TiC at 200°C and for TiB2 at 750°C. The composite ceramics suffer the smallest wear of all materials in the range from 200°C to 500°C. PY - 2006 DO - https://doi.org/10.1002/tt.8 SN - 1354-4063 SN - 1557-685X VL - 12 SP - 99 EP - 111 PB - Coppin CY - Deal AN - OPUS4-32977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kimmari, E. A1 - Podgursky, V. A1 - Simunin, M. A1 - Adoberg, E. A1 - Surzenkov, A. A1 - Viljus, M. A1 - Hartelt, Manfred A1 - Wäsche, Rolf A1 - Sildos, I. A1 - Kulu, P. T1 - Tribological behavior of carbon nanofibers deposited on hard nanocomposite (nc-Ti1 - xAlxN)/(a-Si3N4) coating N2 - Main focus was on the deposition of carbon nanofibers (CNFs) onto the hard nanocomposite (nc-Ti1 - xAlxN)/(a-Si3N4) (nACo®) coating surface and the investigation of the structure and tribological properties of CNFs. The alcohol chemical vapor deposition (ACCVD) method was employed to prepare CNFs and the deposition temperatures were 600 and 700 °C, respectively. Prior to the CNF deposition, Ni catalyst was deposited onto the nACo® surface using the magnetron sputtering. The influence of the deposition temperature on the carbon nanofibers structure was investigated by Raman spectroscopy and scanning electron microscopy (SEM). The higher order degree of CNF structure is observed with increasing deposition temperature. Tribological tests were carried out under fretting contact conditions against Al2O3 ball. It is shown that the coefficient of friction (COF) decreases from 1.0 to 1.2 for the clean nACo® surface to 0.2–0.4 for the CNF layers deposited on the nACo® surface. The roughness of the nACo® surface was varied and a higher durability of the CNF layers deposited on the rougher nACo® surface is found. KW - Carbon nanofiber KW - Coating KW - Fretting KW - Roughness KW - Solid lubrication PY - 2013 DO - https://doi.org/10.1016/j.surfcoat.2013.03.011 SN - 0257-8972 VL - 225 SP - 21 EP - 25 PB - Elsevier Science CY - Lausanne AN - OPUS4-32978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cruzado, A. A1 - Hartelt, Manfred A1 - Wäsche, Rolf A1 - Urchegui, M.A. A1 - Gómez, X. T1 - Fretting wear of thin steel wires. Part 2: Influence of crossing angle N2 - The wear behaviour of thin steel wires has been analyzed under oscillating sliding conditions in crossed cylinders contact geometry. The focus of this analysis was the influence of the crossing angle between the wires on the wear. The wires used had 0.45 mm in diameter and the material was cold-drawn eutectoid carbon steel (0.8% C) with a tensile strength higher than 2800 MPa. Two different types of tests were carried out, the first one representing the influence of the crossing angle for a constant load and the second one representing the influence of the crossing angle with constant contact pressure. In the first type of tests it was seen that as the contact angle decreases the contact pressure decreases too and hence less energy specific wear resistance is observed. As a consequence less wear is produced, thus increasing the life of the wires. In the second type of tests it was seen that with constant contact pressure but different crossing angles, nearly the same energy specific wear resistance was observed. This points at an identical wear behaviour in both type of tests but with a running-in and a steady state period as two different wear periods. The tests showed that the running in period may play an important role in the overall wear particle generation and hence the wear occurring in the steady state period is rather mild. KW - Fretting KW - Wires KW - Contact pressure KW - Crossing angle PY - 2011 DO - https://doi.org/10.1016/j.wear.2011.04.012 SN - 0043-1648 VL - 273 IS - 1 SP - 60 EP - 69 PB - Elsevier CY - Amsterdam AN - OPUS4-31762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harsha, A.P. A1 - Wäsche, Rolf A1 - Hartelt, Manfred T1 - Friction and wear studies of polyetherimide composites under oscillating sliding condition against steel cylinder N2 - Tribological properties of neat polyetherimide (PEI), glass, carbon fiber, and solid lubricants filled PEI composites are presented in this article. The aim of this study was to investigate the friction and wear properties of these composites under dry oscillating sliding condition at room temperature (RT) as well as at elevated temperature (120 °C). The polymer specimens were made to oscillate against steel cylinder as a counterpart. The friction and wear properties of PEI and composites were strongly influenced by the temperature. Incorporation of carbon fiber in the PEI matrix has increased the wear rate at RT, while at elevated temperature this trend was opposite. Abrasive action of carbon fibers has severely damaged the counterpart and resulted in accelerated wear of the composite at RT. Solid lubricants filled (PTFE, MoS2, graphite) along with glass fiber is beneficial in improving the friction and wear performance of the PEI composite at RT, whereas at elevated temperature wear performance was deteriorated. Tribological performance of neat PEI and glass fiber composite was similar with each other at RT. Scanning electron micrographs and optical micrographs of the worn polymer specimens and the steel cylinders was used to study the possible wear mechanisms. The present test results were also compared with data available on the reciprocating wear of PEI and composites in the literature and trends have been reported. PY - 2015 DO - https://doi.org/10.1002/pc.23559 SN - 0272-8397 SN - 1548-0569 VL - 38 IS - 1 SP - 48 EP - 60 PB - Society of Plastics Engineers CY - Manchester, NH AN - OPUS4-34921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Hartelt, Manfred A1 - Weihnacht, V. T1 - Influence of counterbody material on wear of ta-C coatings under fretting conditions at elevated temperatures N2 - The high temperature tribological performance of tetrahedral amorphous carbon coatings has been analyzed at elevated temperatures up to 250 °C in air against three different counterbody materials-steel 100Cr6, a-alumina and silicon nitride. The results show that the counterbody material influences the friction and wear behavior and therefore coating life time strongly. This effect is well known for these coatings at room temperature under dry environmental conditions, equivalent to conditions above 100 °C when water molecules desorb from the surface. However, the sharp difference in tribological performance between silicon nitride on the one hand and alumina and steel on the other hand cannot be understood in this context. Analyzing the friction behavior during the running-in phase, it is evident that only alumina and steel form a stable interface with constant low friction and relatively low wear rates. Silicon nitride forms an unstable interface with fluctuating COF and relatively high wear rates due to its own inherent tendency to tribo-oxidation. KW - Fretting KW - Hard carbon coatings KW - ta-C KW - High temperature KW - Counterbody influence PY - 2009 DO - https://doi.org/10.1016/j.wear.2009.08.041 SN - 0043-1648 VL - 267 IS - 12 SP - 2208 EP - 2215 PB - Elsevier CY - Amsterdam AN - OPUS4-20344 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cruzado, A. A1 - Hartelt, Manfred A1 - Wäsche, Rolf A1 - Urchegui, M.A. A1 - Gómez, X. T1 - Fretting wear of thin steel wires. Part 1: Influence of contact pressure N2 - Different fretting tests of thin steel wires under different conditions (loads, strokes, number of cycles and mean pressures) were performed. The wires used had 0.45 mm in diameter and the material was a cold-drawn eutectoid carbon steel (0.8% C) with a tensile strength over 2800 MPa. The tests were carried out with 90° "crossed cylinders" configuration varying the stroke, normal load and testing time (number of cycles). Afterwards the volumetric wear was obtained using surface profilometry with diamond stylus. With a classical study of the coefficient of wear with respect to the sliding distance, the results show that the wear coefficient increases with normal load and stroke, consequently, for the same sliding distance, the wear produced was higher when the load and/or stroke is increased. In this work, the coefficient of wear is decreasing continuously as the test is running. In order to analyze better the wear behaviour, another method, in which the volumetric wear is compared with respect to the Archard's loading factor, is proposed. As result of this method, two distinctive behaviours were detected; one corresponds to the running-in period with a more aggressive wear behaviour and the second one to the stable steady state period. In all the tests the running-in period was similar with regard to the wear rates but in the stable period the wear rates were increasing with higher loads or strokes. KW - Fretting KW - Wear KW - Wires KW - Contact pressure KW - Unlubricated tests PY - 2010 DO - https://doi.org/10.1016/j.wear.2010.02.017 SN - 0043-1648 VL - 268 IS - 11-12 SP - 1409 EP - 1416 PB - Elsevier CY - Amsterdam AN - OPUS4-21181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartelt, Manfred A1 - Wäsche, Rolf A1 - Djahanbakhsh, Mohammad A1 - Österle, Werner T1 - Vergleich von Standard-Modell- und HIP-Simulator-Untersuchungen an Verschleißschutzschichten für Metall-Keramik-Paarungen bei Endoprothesen KW - Beschichtung KW - Reversierender Gleitverschleiß KW - HIP-Simulation KW - Coating KW - Reciprocating sliding KW - HIP-Simulation PY - 2008 SN - 0724-3472 VL - 55 IS - 1 SP - 21 EP - 25 PB - Expert Verlag CY - Renningen AN - OPUS4-17133 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -