Introduction Nowadays, the demands placed on technical systems are constantly increasing. As a result, the optimization of dry-running clutches and brakes is important. In addition to performance, the focus is also on sustainability and resource efficiency. To exploit the full performance potential of these systems, as much of the intended friction surface as possible must be actively involved in the friction process. To this end, the surface profile of the friction partners is smoothed during the run-in process and a stable friction layer is formed [1-3]. These mechanisms optimize the transmission behavior and are crucial for improving the service life, performance and coefficient of friction stability of the friction systems [4-6]. Until now, research has mainly focused on improving the run-in behavior by modifying the friction lining [7]. This work sets a new accent by investigating the influence of the counter-friction disk on the run-in and wear behavior. The aim is to expand the understanding of the role of the counter-friction disk in friction contact and to exert a targeted influence on tribological behavior. This is achieved within the scope of this work through experimental investigations. Counter-friction disks made of the materials steel C45 and cast-iron material GGG40 are investigated. These were modified by the finishing processes nitrocarburizing and phosphatizing. Both mass-pressed organic friction linings and sintered metallic bronze-based friction linings are used as friction partners. The experimental results should enable a well-founded evaluation of the tribological properties of the counter-friction disks and show how this influences the run-in and wear behavior. The findings are relevant for shortening run-in times and reducing the associated costs for friction system manufacturers. As a result, a run-in system can be implemented directly at the customer. State of research Previous studies on the run-in behavior of dry-running friction pairings have mainly focused on the friction lin- Science and Research 5 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 Optimization of the run-in and wear behavior of dry-running friction systems through the targeted adaptation of the counter-friction disk: Experimental investigations and potentials for sustainable and efficient solutions Timo Hacker, Arne Bischofberger, Katharina Bause, Sascha Ott, Albert Albers* submitted: 17.09.2024 accepted: 21.11.2024 (peer review) Presented at GfT Conference 2024 This paper investigates the friction and wear behavior of dry-running friction systems during the run-in process, focusing on the specific adaptation of the counter-friction disk. The influence of these factors on the run-in behavior is investigated by varying the material and the finishing process of the counter-friction disk. The materials steel C45 and cast iron GGG40 as well as the application of nitrocarburizing and phosphating represent varied parameters. The results show that an improvement in wear properties, performance and coefficient of friction stability can be achieved by optimizing the counter-friction disk. These findings make it possible to increase the efficiency of friction systems. Keywords run-in Brake systems, System tribology, static coefficient of friction, dynamic coefficient of friction, wear coefficient, Phosphating counter-friction disk, Nitrocarburizing counter-friction disk Abstract * Timo Hacker, M. Sc. (corresponding author) Karlsruher Institut für Technologie, Institut für Produktentwicklung (IPEK), Kaiserstraße 10, Karlsruhe Arne Bischofberger, M. Sc.; Dipl.-Ing Katharina Bause; Dipl.-Ing Sascha Ott; Univ.-Prof. Dr.-Ing. Dr. h.c. Albert Albers; IPEK - Institut für Produktentwicklung am KIT - Karlsruher Institut für Technologie lationships between the coefficients of friction and the wear coefficient before and after run-in are investigated for different variants of counter-friction disks. A defined methodical procedure is developed for the experimental investigations with application-oriented load collectives. For this purpose, the following characteristic values are defined to quantify the influence of the counter friction disk: the static and dynamic friction coefficient and the wear coefficient. The tests are carried out at room temperature. The test sequence is divided into test series before the run-in and after the run-in to determine the static and dynamic coefficients of friction and the wear coefficient. At the beginning of the tests, the tribological system is examined in its new condition. For this purpose, measurements are taken to determine the wear and the static and dynamic coefficient of friction after the friction pairing has been installed. To keep the influence on the tribological system as low as possible, only three measurements are carried out to determine the static coefficient of friction in the new condition. During run-in, the friction pairings undergo a total of 1,000 braking cycles. The number of cycles for the run-in was determined based on the findings from preliminary tests. Once a certain number of braking cycles is reached under constant conditions, the coefficient of friction reaches an almost constant level [2]. After run-in, the measurements to determine the static and dynamic coefficient of friction and a final weight measurement are carried out again in the cooled system state Dynamic coefficient of friction Figure 1 shows the schematic test sequence of a braking cycle to determine the dynamic coefficient of friction. The drive accelerates the flywheel mass and the brake pad carrier to the specified speed and is then decoupled by opening the electromagnetic clutch. The test head is then closed via the axial-alternating slide, which leads to the rotating friction lining being braked to a standstill by the frictional contact with the counter-friction disk. Static coefficient of friction Figure 2 shows the schematic test sequence for determining the static coefficient of friction. First, the test head with friction lining is rotated load-free for a random period of time. This ensures that the same macroscopic surface properties do not meet and form the frictional contact during the next switching operation. An axial force is then applied, causing the friction lining to be pressed against the counter-friction disk until the nominal surface pressure is reached. The torque is then increased via the electric motor until the friction contact breaks loose. Once the test is complete, the axial force is reduced. Science and Research 6 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 ing [7]. The influence of different load collectives on the coefficient of friction and the surface change with different friction linings is analyzed. In accordance with [8], the run-in behavior is influenced by the load, the environment and also by the properties of the counter friction disk. However, the influence of the counter-friction disk on the tribological behavior of dry-running friction systems has not yet been sufficiently researched. According to Severin and Musiol, a friction layer forms during the run-in process, which protects the underlying layer from thermal overload [1].Gauger describes a quasi-stationary state of the friction layer that occurs during the run-in process, in which constant friction and wear properties prevail [9]. Trepte extends the evaluation of the run-in process by analysing wear particles, which show a stabilization of the particle size after several braking processes [2]. Investigations by Tsang, Jacko and Rhee show that brand-new pairings (organic friction lining with cast iron counter-friction disk) cause high wear during the formation of the friction layer, while the friction partners are smoothed [3].Neumann and Groganz as well as Bergheim show the influence of the load selective on the wear [5, 6]. In their work, Neumann and Groganz focus on the creation of a test collective with which the total wear in an application can be predicted as well as possible [5]. Bergheim concentrates on the influence of temperature as the central variable of the load spectrum and shows the influence of the geometry of the test specimens on wear [10]. Kleinlein is investigating the effect of different friction material combinations and environmental conditions on the friction and wear behavior of dry-running clutches by combining different friction linings with counter-friction disks in different materials. The counter-friction disk made of austenitic steel proves to be particularly wear-promoting. [11] Völkel investigated how the influence of steel plates affects the run-in behavior of wet-running clutches. The steel plates were produced using different manufacturing and finishing processes. The results show that the surface characteristics of the steel plates in particular have a significant influence on the run-in behavior of the friction pairing. [12] The previously cited studies show a correlation between the run-in and wear behavior of friction pairings through the design characteristics of the friction pairing. However, the previous studies did not focus on the influences of the counter-friction disks used for run-in. Research objective and method The experiments aim to gain initial insights into the influence of the counter-friction disk on the run-in and wear behavior of dry-running friction pairings. The re- Test environment The experimental investigations are carried out at the IPEK - Institute for Product Engineering at the KIT - Karlsruhe Institute of Technology. The test environment (Figure 3), which was developed according to the IPEK X-in-the-loop approach [14], is used to carry out reproducible tests on dry-running friction pairings under load collectives close to the application [15-17]. The inertias and stiffnesses of the residual systems from the application are mapped and the interaction effects with the residual system are represented realistically. To carry out the tests, the output side is mechanically blocked so that the tests are carried out as brake applications. During the tests, normal force, speed, torque, the travel distance of the axial force actuator and the temperature are measured. The applied axial force is recorded by a force sensor positioned between the test head and the axial force actuator. The transmitted torque is measured via a torque measuring hub, which is located as close as possible to the friction contact. This ensures that as little measurement distortion as possible is recorded due to other frictional torques, such as the bearings. The surface pressure, friction work, friction power, coefficient of friction and the gradient coefficient of friction are calculated from this data. To determine the temperature in the friction contact or the surface temperature, twelve thermocouples are inserted into the counter-friction disk. Results The results of the tests with nine different friction pairings are examined below. The different variants of the counter-friction disk are examined for their influence on the run-in and wear behavior. A mass-pressed organic friction lining is used as the friction partner for six pairings. For three pairings, it is investigated whether the influence of the counter-friction disk with a sintered metal bronze-based friction lining has a different behavior. The following friction pairings are investigated, see Table 1: Science and Research 7 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 Figure 1: Schematic test sequence for determining the dynamic coefficient of friction based on [7] Figure 2: Schematic test procedure for determining the static coefficient of friction based on [13] Static coefficient of friction Figure 5 shows the statistical evaluation of the static coefficient of friction. The box plot of the three repetitions of the static coefficient of friction measurement before the run-in is shown on the left and the ten measurements after the run-in are shown on the right. Most friction pairings show an increase in the static coefficient of friction after run-in. Friction pairings 2, 5 and 9 show a greater scattering of the measured coefficient of friction before run-in. The analysis of the static coefficient of friction of the friction pairings shows that the first coefficient of friction of each pairing exhibits the greatest deviation, while the subsequent values are close to each other. After the run-in, all friction pairings except friction pairings 8 show a small scatter. The outliers in friction pairings 1, 4 and 9 occurred at the beginning of the series of measurements. In the case of friction pairing 8, the large scatter is due to a drop in the static coefficient of friction towards the end of the test series. Science and Research 8 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 Dynamic coefficient of friction Figure 4 shows the statistical evaluation of the dynamic coefficient of friction. The box plot of the ten repetitions of the measurement of the dynamic coefficient of friction before the run-in is shown on the left and the ten measurements after the run-in are shown on the right. For friction pairings 1 and 8, the data shows very little scatter and a symmetrical distribution before the run-in. Friction pairings 2, 3, 4 and 5 show a moderate scatter around the mean value. However, the distribution is still relatively consistent. Friction pairings 6, 7 and 9 show a wider spread and possible asymmetry before the run-in. After the run-in, friction pairings 1, 2, 3, 4, 6 and 9 show an even distribution with few to no outliers. Friction pairings 5, 7 and 8 still show a moderate spread after the run-in. For most friction pairings, the mean dynamic coefficient of friction after run-in is lower than the values before run-in. This indicates an improvement in the active friction layer or a smoothing of the contact surfaces during run-in. Friction pairings 7 and 9 exhibit a higher mean dynamic coefficient of friction after run-in. Figure 3: Brake test bench for testing dry-running friction systems based on [7] Counter-friction disk friction lining friction pairing 1 C45 organic friction pairing 2 C45, nitrocarburized organic friction pairing 3 C45, phosphated organic friction pairing 4 GGG40 organic friction pairing 5 GGG40, nitrocarburized organic friction pairing 6 GGG40, phosphated organic friction pairing 7 C45, phosphated sintered metal friction pairing 8 GGG40, nitrocarburized sintered metal friction pairing 9 GGG40, phosphated sintered metal Table 1: Test pairings C45 organic C45, nitrocarburized organic C45, phosphated organic GGG40 organic GGG40, nitrocarburized organic GGG40, phosphated organic C45, phosphated sintered metal GGG40, nitrocarburized sintered metal GGG40, phosphated sintered metal organic organic organic organic organic organic sintered metal sintered metal sintered metal g g Science and Research 9 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 1 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 2 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 3 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 4 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 5 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 6 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 7 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 8 before run-in after run-in 0.2 0.25 0.3 0.35 0.4 0.45 0.5 dynamic coefficient of friction Friction pairing 9 Figure 4: Statistical evaluation of the dynamic coefficient of friction before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 1 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 2 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 3 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 4 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 5 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 6 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 7 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 8 before run-in after run-in 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 static coefficient of friction Friction pairing 9 Figure 5: Statistical evaluation of the static coefficient of friction Most surfaces show an increase in roughness after exposure. An increase in the height amplitude is also observed, which indicates an increase in the peak depth and a change in the mean height Sv after stressing. For some surfaces, the differences in skewness (Ssk) show that the asymmetry of the surfaces has changed. The kurtosis also shows changes for most surfaces, with a tendency for the kurtosis to increase. Due to the finishing processes, both counter-friction disks show a smaller increase in the surface characteristics after run-in. Phosphating causes a smaller increase in the roughness of the C45 steel counter-friction disk than nitrocarburising. The reverse is true for the counterfriction disk made of GGG40 cast iron. When using the sintered metallic friction lining, the phosphated C45 counter-friction disk shows a similar development of the characteristic values as when using the organic friction lining. With the GGG40 counter-friction disk, the sintered metallic friction lining causes a reduction in the characteristic values. This indicates a stronger smoothing of the surfaces. Discussion Various findings can be derived from the experimentally determined dynamic and static coefficient of friction before and after the tun-in. By comparing the coefficient of friction at the different test times, it is possible to determine how the friction conditions have changed because of the run-in. The analysis shows that different pairings exhibit different wear behavior. Some pairings exhibit very high consistency and low wear rates, while others show significantly higher wear rates and greater variability. This may be due to the material composition, the surface treatment or the operating conditions of the friction surfaces. For most friction pairings, the mean dynamic coefficient of friction decreases after run-in. This indicates that the surfaces are better matched to each Science and Research 10 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 Wear coefficients Figure 6 shows the wear coefficients of the nine friction pairings across the run-in. Friction pairings 1 and 2 have the lowest wear coefficients and a low scatter. Friction pairs 2, 6, 8 and 9 show higher wear coefficients with moderate to low scatter. Friction pairings 3, 4 and 5 have higher wear coefficients with higher scatter. The finishing processes lead to an increase in the wear coefficient for the steel C45 counter-friction disk when using an organic mass-pressed friction lining (see friction pairings 1, 2 and 3). In the case of the phosphated steel C45 counter-friction disk, the sintered metal friction lining causes less wear than the organic friction lining (see friction pairings 2 and 7). In the case of the counter-friction disk made of cast iron material GGG40, nitrocarburizing (friction pairing 5) leads to an increase and phosphating (friction pairing 6) to a reduction in the wear coefficient when using a sintered metallic bronze-based friction lining. In the case of the counter-friction disk made of cast iron material GGG40, the finishing processes show a diametrical behavior of the wear when using the sintered metallic friction lining (friction pairing 8 and 9) compared to the organic friction lining (friction pairing 2 and 3). Surface analysis The figure shows the differences between the surface characteristics before and after the run-in of the nine friction pairings. A positive difference means that the value after the run-in is higher than before the run-in. Three measuring fields are defined on the counter-friction disc of the friction pairings. The position is programmed identically for each measurement. The measuring fields on the counter-friction disk have an area of 10 mm 2 and are offset by 120 degrees to each other. The measurements are carried out in new condition and after running-in. Friction pairing 1 Friction pairing 2 Friction pairing 3 Friction pairing 4 Friction pairing 5 Friction pairing 6 Friction pairing 7 Friction pairing 8 Friction pairing 9 0 50 100 150 Coefficient of wear in mm³/ MJ Figure 6: Statistical evaluation of the wear coefficient over the run-in other through the run-in process and a friction-active layer is formed, which leads to improved frictional efficiency. Friction pairings 7 (C45, phosphated) and 9 (GGG40, phosphated) show a higher mean dynamic coefficient of friction after run-in, which may indicate the formation of abrasive particles by the sintered metallic friction lining. In the case of the steel C45 counter-friction disk in combination with an organic friction lining, nitrocarburizing leads to a reduction in the dynamic coefficient of friction by around 5 % and the static coefficient of friction by around 27 %. This is accompanied by a significant increase in wear. In contrast, phosphating causes the dynamic coefficient of friction in the tests to remain at a similar level to the untreated counter-friction disk, while the static coefficient of friction increases by more than 15 %. However, the phosphating causes a significant increase in wear. In the case of the steel C45 counter-friction disk with a sintered metal friction lining, the dynamic coefficient of friction increases after run-in, while wear remains low. For the counter-friction disk made of cast iron material GGG40 with an organic friction lining, nitrocaburation leads to a lower dynamic coefficient of friction and increased wear in the tests. In addition, the static coefficient of friction is around 21 % lower and shows a large scatter before the run-in. Phosphating leads to a reduction in the dynamic coefficient of friction of around 5 % and the static coefficient of friction of around 4 %. However, it causes a reduction in wear. Nitrocarburizing shows an increase in the wear coefficient, while phosphating causes a reduction. This may indicate that the finishing processes influence the material properties differently. Phosphating appears to improve wear resistance, while nitrocarburizing may lead to increased wear. The finishing processes show different behavior when using sintered metallic and organic friction linings, indicating the importance of surface treatment and material selection. Science and Research 11 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 S q -2 0 2 4 6 8 μm S sk 0 5 10 S ku -100 0 100 200 S p -50 0 50 100 μm S v -100 0 100 μm S z -50 0 50 100 μm Measuring field 1 Measuring field 2 Measuring field 3 S a -2 0 2 μm Figure 7: Difference in the parameters of the surface analysis before and after the run-in S q S sk S ku S p S v S z S a S q S sk S ku S p S v S z S a [3] P. H. Tsang, M. G. Jacko und S. K. Rhee, “Comparison of chase and inertial brake dynamometer testing of automotive friction materials,” Wear, Jg. 103, S. 217-232, 1985. [4] H. Czichos und K.-H. Habig, Tribologie-Handbuch: Tribometrie, Tribomaterialien, Tribotechnik, 3. Aufl. Vieweg+Teubner Verlag; Springer Fachmedien Wiesbaden GmbH, 2010. [5] K. Neumann und O. Groganz, “Verschleißverhalten von organischen Kupplungsbelägen. Steigerung der Praxisnähe durch neue Prüfkollektive.,” (Kupplungen und Kupplungssysteme in Antrieben 2015), S. 257-268. [6] M. Bergheim, “Organisch gebundene Kupplungsbeläge Möglichkeiten und Grenzen,” VDI-Berichte, Jg. 1323, S. 527-548, 1997. [7] R. Fehrenbacher, A. Fischer, S. Ott, I. Cokdogru, D. Gierling und F. Mazurek, “FVA 860 I Abschlussbericht: Vorkonditionierung von trockenlaufenden Reibpaarungen für eine stabile Reibfunktion im Feld,” Nr. 1472, S.1-236, 2022. [8] L. Deters, A. Fischer, E. Santer und U. Stolz, “GfT Arbeitsblatt 7 - Tribolgoie: Verschleiß, Reibung - Definitionen, Begriffe, Prüfung,” S. 1-50, 2002. [9] D. Gauger, Wirkmechanismen und Belastungsgrenzen von Reibpaarungen trockenlaufender Kupplungen (VDI Reihe 1 Nr. 301) (Konstruktionstechnik/ Maschinenelemente). Düsseldorf: VDI Verlag, 1998. [10] P. J. Blau und B. C. Jolly, “Wear of truck brake lining materials using three different test methods,” Wear, Jg. 259, S. 1022-1030, 2005. [Online]. Verfügbar unter: http: / / dx.doi.org/ 10.1016/ j.wear.2004.12.022 [11] D. Severin und C. Kleinlein, “Einfluss der Reibwerkstoffkombination und der Umweltbedingungen auf das Reibverhalten trockenlaufender Kupplungen. Abschlussbericht zum Forschungsvorhaben 215/ II der Forschungsvereinigung Antriebstechnik e.V. (FVA), Heft 636,” 2001. [12] K. Völkel, H. Pflaum und K. Stahl, “Einflüsse der Stahllamelle auf das Einlaufverhalten von Lamellenkupplungen,” Forsch Ingenieurwes, Jg. 83, Nr. 2, S. 185-197, 2019, doi: 10.1007/ s10010-019-00303-2. [13] R. Fehrenbacher, S. Ott, I. Cokdogru und J. Huber, “FVA 806 I Abschlussbericht: Entwicklung einer Prüfmethode zur Ermittlung des statischen Reibmomentes (Losreißmoment) trockenlaufender Kupplungen und Bremsen auf Komponentenebene,” [14] A. Albers, M. Behrendt, S. Klingler und K. Matros, “Verifikation und Validierung im Produktentstehungsprozess,” in Lindemann (Hg.) 2016 - Handbuch Produktentwicklung, S. 541-569. [15] A. Albers, S. Ott und J. Kniel, FVA 607 II: Kupplungsmodell Trockenlauf II: Einfluss der Reibbelagsgeometrie auf das tribologische Verhalten: Forschungsvorhaben Nr. 607 II, 2015. [16] A. Albers, S. Ott und N. Schepanski, FVA 737: Leistungsgrenzen Trockenlauf: Methode zur Bestimmung der Leistungsgrenzen trockenlaufender Friktionssysteme, 2016. [17] T. Klotz, S. Ott und A. Albers, “Analyse des Schädigungs- und Erholungsverhaltens trockenlaufender Friktionspaarungen,” Forschung im Ingenieurwesen, Nr. 83, S. 209- 218, 2019. Science and Research 12 Tribologie + Schmierungstechnik · volume 71 · issue 5-6/ 2024 DOI 10.24053/ TuS-2024-0033 The results show that the properties of the counter-friction disks and the type of friction lining have a significant influence on the friction behavior and wear. Phosphating stabilizes the coefficient of frictions behavior in a large proportion of the friction pairs investigated and leads to a reduction in wear. Nitrocarburizing has different effects on wear depending on the friction lining. The material properties, the finishing processes and the use of different friction linings influence both the dynamic and static coefficients of friction as well as the wear rate. The knowledge gained enables a targeted, more efficient and sustainable design of future friction pairings, which can be optimally adapted to the respective applications. Outlook To further deepen the knowledge gained, the choice of material combination is to be expanded in future investigations. The combinations of steel C45 and cast iron material GGG40 with organic and sintered metal friction linings investigated so far provide valuable findings, but it remains to be seen how the tribological behavior of other potential material pairings will turn out under similar conditions. The influences of the finishing processes should also be investigated further to be able to control the run-in and wear behavior even more specifically. In addition, it makes sense to focus on the effects of the counter friction properties under different load collectives. Different load profiles, speeds and temperature scenarios could significantly change the friction and wear dynamics [5, 6, 9], which is of great importance in real application scenarios. Acknowledgement The investigations presented in the publication were performed within the FVA-Project 964 I. The authors acknowledge the funding of the research project. The FVA-Projekt 964 I “Einfluss Gegenreibscheibe” is funded by the “Forschungsvereinigung Antriebstechnik e.V. (FVA)“. Literature [1] D. Severin und F. Musiol, “Der Reibprozeß in trockenlaufenden mechanischen Bremsen und Kupplungen,” Konstruktion, Jg. 47, S. 59-68, 1995. [2] S. Trepte, “Einlaufverhalten technischer Reibbeläge,”Automobiltechnische Zeitschrift, Jg. 103, Nr. 12, 2001.