TY - CONF A1 - Österle, Werner A1 - Deutsch, Cornelius A1 - Dörfel, Ilona A1 - Gradt, Thomas A1 - Häusler, Ines A1 - Orts-Gil, G. A1 - Prietzel, C. A1 - Schneider, Thomas T1 - Final outcome of a fundamental research project on tribofilms formed during automotive braking, Part 1: Experimental studies T2 - EuroBrake 2014 (Proceedings) N2 - In order to obtain a better understanding of the role of tribofilms during automotive braking, their structures were investigated and the essential features identified. Next, different ingredient combinations were studied by preparing some model materials with simpler compositions than real tribofilms. A test method was developed for verifying the tribological properties of the model materials and for comparison with results obtained with numerical sliding simulations of such structures. Prerequisites of good brake Performance properties were identified. Although the coefficient of friction could be varied in a wide ränge, smooth sliding conditions could only be achieved with values smaller than 0.4. Tests with artificial third body powders turned out to be useful as screening method for the selection of raw materials for brake pad formulations. T2 - EuroBrake 2014 CY - Lille, France DA - 13.05.2014 KW - Tribofilm KW - Third body KW - Pad ingredients KW - Ball milling KW - Pin-on-disc test PY - 2014 SN - 978-0-9572076-4-6 SP - 1 EP - 8 PB - FISITA CY - London AN - OPUS4-35039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dmitriev, A.I. A1 - Kloß, Heinz A1 - Österle, Werner T1 - Final outcome of a fundamental research project on tribofilms formed during automotive braking, Part 2: Numerical simulation T2 - EuroBrake 2014 (Proceedings) N2 - In part 1 it was shown that tribofilms usually are 100 nm thick and exhibit a multiphase nanocrystalline structure. The objective of our modelling efforts was to obtain a better understanding of the sliding behaviour and associated friction properties and to study the impact of internal and external parameters on these properties. The method of movable cellular automata (MCA) was used. The third bodies were considered as aggregates of linked nanoparticles which may decompose and form a layer of granulär material, the so-called mechanically mixed layer (MML), if certain fracture criteria are fulfilled. The basic model structure which consists of Fe3Ü4 nanoparticles with 13 % graphite inclusions was used. In order to assess the robustness of the model the following parameter studies were performed. The pressure ränge at an asperity contact was varied between 15 and 50 MPa. The mechanical properties of the oxide were varied between brittle and ductile behaviour corresponding to room temperature and high temperature behaviour. The mechanical properties of the soft ingredient were varied + 50 % of the properties of graphite. The influence T2 - EuroBrake 2014 CY - Lille, France DA - 13.05.2014 KW - Tribofilm KW - Third body KW - Dry friction KW - Modelling KW - Movable cellular automata PY - 2014 SN - 978-0-9572076-4-6 SP - 1 EP - 9 PB - FISITA CY - London AN - OPUS4-35040 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 T2 - EuroBrake 2012 (Proceedings) T2 - EuroBrake 2012 CY - Dresden, Germany DA - 2012-04-16 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 - CONF A1 - Dmitriev, A.I. A1 - Österle, Werner T1 - Sliding simulations with variable amounts of copper and graphite mixed with magnetite T2 - Proceedings EuroBrake 2016 N2 - Copper is one of the most important components in brake pads and its amount can reach up to 14%. In spite of a number of positive features copper usage in brake pad formulations has recently become the subject of considerable discussions, primarily due to concerns about potential risks related to environmental impacts of copper particles. So, for developing new pad formulations with possible replacements of copper content, it is very important to understand the functionality of copper additions to brake friction materials. In the paper theoretical investigation of the role of copper as a pad ingredient was carried out on the basis of modelling by the method of movable cellular automata (MCA). Our previous studies show that copper as a constituent of the tribofilm formed during braking provides smooth sliding by forming a granular layer of mechanically mixed materials from the friction layers. In the present study the concentration of copper particles in a Fe3O4-matrix was varied systematically in the range 5.5-28 vol. % and compared to mixtures with the same amount of graphite nanoparticles. The sliding simulations were performed while assuming material properties at 500°C in order to assess the beneficial role of copper during severe braking conditions corresponding to fading cycles during dynamometer testing. T2 - EuroBrake 2016 CY - Milano, Italy DA - 13.06.2016 KW - Movable cellular automata KW - Copper KW - Sliding simulation KW - Third body KW - Tribofilm PY - 2016 UR - www.eurobrake.net VL - EB2016-SVM-054 SP - 1 EP - 7 PB - FISITA AN - OPUS4-37938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -