TY - JOUR A1 - Österle, Werner A1 - Griepentrog, Michael A1 - Gross, Thomas A1 - Urban, Ingrid T1 - Chemical and microstructural changes induced by friction and wear of brakes N2 - The chemical and microstructural changes occurring during braking simulation tests at the surface of a conventional brake pad material were investigated mainly by scanning and transmission electron microscopy and surface analytical techniques. It can be shown that patches of a third body material develop, comprising a compositional mix of all constituents of the pad and iron oxides from the disk. Milled debris particles still have the crystal structure of barite, the major phase of the pad material, but the grain size is reduced drastically to the nanometer scale. The major wear mechanism is delamination of filler particles from the organic binder, supported by local degradation of the phenolic resin during asperity heating. Quartz crystals are preserved thereby adopting the function of primary contact areas. KW - Brake KW - Third body material KW - Friction layer KW - Electron microscopy PY - 2001 U6 - https://doi.org/10.1016/S0043-1648(01)00785-2 SN - 0043-1648 VL - 251 SP - 1469 EP - 1476 PB - Elsevier CY - Amsterdam AN - OPUS4-2371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seah, M.P. A1 - Spencer, S.J. A1 - Bensebaa, F. A1 - Vickridge, I. A1 - Danzebrink, H. A1 - Krumrey, M. A1 - Gross, Thomas A1 - Österle, Werner A1 - Wendler, E. A1 - Rheinländer, B. A1 - Azuma, Y. A1 - Kojima, I. A1 - Suzuki, N. A1 - Suzuki, M. A1 - Tanuma, S. A1 - Moon, D.W. A1 - Lee, H.J. A1 - Cho, H.M. A1 - Chen, H.Y. A1 - Wee, A. T. S. A1 - Osipowicz, T. A1 - Pan, J.S. A1 - Jordaan, W.A. A1 - Hauert, R. A1 - Klotz, U. A1 - van der Marel, C. A1 - Verheijen, M. A1 - Tamminga, Y. A1 - Jeynes, C. A1 - Bailey, P. A1 - Biswas, S. A1 - Falke, U. A1 - Nguyen, N.V. A1 - Chandler-Horowitz, D. A1 - Ehrstein, J.R. A1 - Muller, D. A1 - Dura, J.A. T1 - Critical review of the current status of thickness measurements for ultrathin SiO2 on Si - Part V: Results of a CCQM pilot study N2 - Results are reported from a pilot study under the Consultative Committee for Amount of Substance (CCQM) to compare measurements of and resolve any relevant measurement issues in, the amount of thermal SiO2 oxide on (100) and (111) orientation Si wafer substrates in the thickness range 1.5 - 8 nm. As a result of the invitation to participate in this activity, 45 sets of measurements have been made in different laboratories using 10 analytical methods: medium-energy ion scattering spectrometry (MEIS), nuclear reaction analysis (NRA), RBS, elastic backscattering spectrometry (EBS), XPS, SIMS, ellipsometry, grazing-incidence x-ray reflectrometry (GIXRR), neutron reflectometry and transmission electron microscopy (TEM). The measurements are made on separate sets of 10 carefully prepared samples, all of which have been characterised by a combination of ellipsometry and XPS using carefully established reference conditions and reference parameters. The results have been assessed against the National Physical Laboratory (NPL) data and all show excellent linearity. The remaining data sets correlate with the NPL data with average root-mean-square scatters of 0.15 nm, half being better than 0.1 nm and a few at or better than 0.05 nm. Each set of data allows a relative scaling constant and a zero thickness offset to be determined. Each method has an inherent zero thickness offset between 0 nm and 1 nm and it is these offsets, measured here for the first time, that have caused many problems in the past. There are three basic classes of offset: water and carbonadeous contamination equivalent to ~1 nm as seen by ellipsometry; adsorbed oxygen mainly from water at an equivalent thickness of 0.5 nm as seen by MEIS, NRA, RBS and possibly GIXRR; and no offset as seen by XPS using the Si 2p peaks. Each technique has a different uncertainty for the scaling constant and consistent results have been achieved. X-Ray photoelectron spectroscopy has large uncertainties for the scaling constant but a high precision and, critically, if used correctly, has zero offset. Thus, a combination of XPS and the other methods allows the XPS scaling constant to be determined with low uncertainty, traceable via the other methods. XPS laboratories returning results early were invited to test a new reference procedure. All showed very significant improvements. The reference attenuation lengths thus need scaling by 0.986 ± 0.009 (at an expansion factor of 2) deduced from the data for the other methods. Several other methods have small offsets and, to the extent that these can be shown to be constant or measurable, then these methods will also show low uncertainty. Recommendations are provided for parameters for XPS, MEIS, RBS and NRA to improve their accuracy. KW - Calibration KW - Ellipsometry KW - GIXRR KW - Interlaboratory study KW - MEIS KW - Neutron reflectometry KW - NRA KW - RBS KW - Silicon dioxide KW - SIMS KW - XPS PY - 2004 U6 - https://doi.org/10.1002/sia.1909 SN - 0142-2421 SN - 1096-9918 VL - 36 IS - 9 SP - 1269 EP - 1303 PB - Wiley CY - Chichester AN - OPUS4-5549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Seah, M.P. A1 - Spencer, S.J. A1 - Bensebaa, F. A1 - Vickridge, I. A1 - Danzebrink, H. A1 - Krumrey, M. A1 - Gross, Thomas A1 - Österle, Werner A1 - Wendler, E. A1 - Rheinländer, B. A1 - Azuma, Y. A1 - Kojima, I. A1 - Suzuki, N. A1 - Suzuki, M. A1 - Tanuma, S. A1 - Moon, D.W. A1 - Lee, H.J. A1 - Cho, H.M. A1 - Chen, H.Y. A1 - Wee, A. T. S. A1 - Osipowicz, T. A1 - Pan, J.S. A1 - Jordaan, W.A. A1 - Hauert, R. A1 - Klotz, U. A1 - van der Marel, C. A1 - Verheijen, M. A1 - Tamminga, Y. A1 - Jeynes, C. A1 - Bailey, P. A1 - Biswas, S. A1 - Falke, U. A1 - Nguyen, N.V. A1 - Chandler-Horowitz, D. A1 - Ehrstein, J.R. A1 - Muller, D. A1 - Dura, J.A. T1 - Ultra-thin SiO2 on Si, Part V: Results of a CCQM Pilot Study of Thickness Measurements KW - SiO2 KW - Thin films KW - Thickness KW - XPS KW - Ellipsometry KW - TEM PY - 2003 SN - 1473-2734 SP - 57 pages AN - OPUS4-4118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Orts Gil, Guillermo A1 - Gross, Thomas A1 - Deutsch, Cornelius A1 - Hinrichs, R. A1 - Vasconcellos, M.A.Z. A1 - Zoz, H. A1 - Yigit, D. A1 - Sun, X. T1 - Impact of high energy ball milling on the nanostructure of magnetite-graphite and magnetite-graphite-molybdenum disulphide blends N2 - Different, partly complementary and partly redundant characterization methods were applied to study the transition of magnetite, graphite and MoS2 powders to mechanically alloyed nanostructures. The applied methods were: Transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), Raman spectroscopy (RS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The main objective was to prepare a model material providing the essential features of a typical tribofilm forming during automotive braking, and to assess the impact of different constituents on sliding behaviour and friction level. Irrespective of the initial grain size, the raw materials were transferred to a nanocrystalline structure and mixed on a nanoscopic scale during high energy ball milling. Whereas magnetite remained almost unchanged, graphite and molybdenum disulphide were transformed to a nanocrystalline and highly disordered structure. The observed increase of the coefficient of friction was attributed to a loss of lubricity of the latter ingredient due to this transformation and subsequent oxidation. KW - Ball milling KW - Mössbauer spectroscopy KW - Raman spectroscopy KW - Transmission electron microscopy KW - X-ray diffraction KW - X-ray photoelectron spectroscopy PY - 2013 U6 - https://doi.org/10.1016/j.matchar.2013.09.007 SN - 1044-5803 SN - 1873-4189 VL - 86 SP - 28 EP - 38 PB - Elsevier Inc. CY - New York, NY AN - OPUS4-29697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -