TY - CONF A1 - Woydt, Mathias T1 - Recent work of the global SRV working group and the development trend of SRV standards N2 - „Cliff“-testing by using SRV The identification in engine or gear tests of the induction time or off-set point („cliff“), after which wear and friction increased. “Cliff” testing as auxiliary method supports the interpretation of engine tests, as it enhances the values of expensive engine tests, because it enables correlations between friction & wear, either from engine or in SRV tests, with additive depletion, oxidation, viscometrics and dispersancy/detergency. Oil samples taken in discrete intervals and “Cliff” tested monitors the evolution of tribological and functional properties versus engine running time. “Cliff” testing by using SRV is a purposeful tool in order to secure and accelerate metallurgical developments and the development of lubricant formulations. T2 - Working Group Meeting about SRV in China 2016 CY - Beijing, China DA - 05.04.2016 KW - SRV KW - Standards KW - China PY - 2016 AN - OPUS4-35747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burbank, John A1 - Woydt, Mathias T1 - Optimization of pre-conditioned cold work hardening of steel alloys for friction and wear reductions under slip-rolling contact N2 - The goal of reducing CO2 emissions in the automobile industry has led to the development of increasingly efficient lightweight material solutions that yield enhanced performance. In light of this goal, this current work involves the optimization of the pre-conditioning of novel, high toughness steel bearings without thermo-chemical treatment, with the aim of transferring the running-in phase into the final step of the mechanical finishing process. A case-hardened gear steel and two novel non-case-hardened steels were evaluated. KW - Work hardening KW - Steel KW - Gear KW - Bearing KW - Residual stress KW - Hardness PY - 2016 DO - https://doi.org/10.1016/j.wear.2016.01.011 SN - 0043-1648 VL - 350-351 SP - 141 EP - 154 PB - Elsevier B.V. CY - Amsterdam, u.a. AN - OPUS4-35665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merryweather, S. A1 - Zweifel, D. A1 - Woydt, Mathias ED - Franek, F. ED - Bartz, Wilfried J. ED - Pauschitz, A. ED - Vizintin, J. ED - Ciulli, E. ED - Crockett, R. T1 - Fuel economy of engine oils based on polyalkylene glycols N2 - The driver for automotive OEMs to work on alternative engine oils is the need for fuel economy and no adverse effect of the engine oil on the durability of particulate filters and catalysts. The alternative engine oils should for mid-term also comply with a positive environmental Profile. T2 - 3rd European Conference on Tribology and 4th Vienna International Conference on Nano-Technology CY - Vienna, Austria DA - 07.06.2011 KW - Biomotox KW - Head capacity KW - Fuel economy KW - Drain KW - Polyglycol KW - Polypropylene glycol KW - Polyalkylene glycol KW - Polybutylene glycol PY - 2011 SN - 978-3-901657-38-2 SP - 25 EP - 34 PB - MDH Media GesmbH CY - Wien AN - OPUS4-35671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tailoring the functional properties of niobium carbide N2 - Several phases, like Nb₄C₃, Nb₆C₅ and other short and long range ordered phases occur in the region of homogeneity of NbCₓ (0,75≤ x ≤1.0) in the binary phase diagram. Properties, like micro-hardness, hot hardness, sliding wear resistance, elastic modulus and toughness can be tailored by the C/Nb ratio, the addition of secondary carbides and the type of binder. Supporting results from different grades with varying C/Nb ratio or binder types were illuminated. Thus, the NbC system offers to producers a wider process window, than WC. The impact of These tailored properties on sliding wear and cutting performance was illuminated by tribological and machining results. Niobium is today largely available. NbC can be synthesized by carbothermal conversion of Nb₂O₅ or be metallurgically grown and leached out, provides comparably low friction in many relevant tribo-contacts and displays low wear. NbC and Nb₂O₅ have so far no REACH classification related to human toxicology and are not listed as substances of very high concern contrary to WO₃ and Co₃O₄. T2 - 40th International Conference and Exposition on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 24.01.2016 KW - Niobium carbide KW - Hard metal KW - Wear KW - Friction KW - Machining KW - Cutting KW - Metal matrix composite PY - 2016 SP - Paper: 2347292, 1 EP - 13 AN - OPUS4-35640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - The use of niobium carbide (NBC) as cutting tools and for wear resistant tribosystems T2 - 10. Int. Conf. on the Science of Hard Materials CY - Cancún, Mexico DA - 2014-03-10 PY - 2014 AN - OPUS4-30336 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tribological background for the use of niobium carbide (NbC) as cutting tools and for wear reistant tribosystems T2 - Tungsten, Refractory & Hardmaterials Conf. CY - Orlando, FL, USA DA - 2014-05-18 PY - 2014 AN - OPUS4-31052 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Substituting tungsten carbide (WC) as cutting tools and for wear protection by niobium carbide (NbC) N2 - As a refractory carbide, niobium carbide (NbC) is today still a forgotten carbide with hidden properties, such as wear resistance, thus qualifying NbC for the group of tribological materials with enhanced wear resistance. Several phases, like Nb₄C₃, Nb₆C₅ and other short and long range ordered phases occur In the region of homogeneity of NbCx (0,75≤ x ≤1.0) in the binary phase diagram, which enable the tailoring of properties and offers a much wider process window than known from WC. The type binder (Co, Ni, NiMo) and its concentration as well as the sintering process (SPS, liquid phase sintering) determine the box “hardness-toughness”, which will be illuminated based on more than 100 grades. The impact of these tailored properties on sliding wear (T= 22/400°C; v= 0,1-10 m/s) and cutting performance will be illuminated by tribological and machining results. Cutting test results under emulsion and coolant-free operation of cobalt and Fe3Al bonded, straight NbC versus WC based inserts against different alloys (C60, 100Cr6, 42CrMo4, X90CrMoV18, 300WA, GG35) will be highlighted. T2 - STLE 2016 Annual Meeting and Exhibition CY - Las Vegas, NV, USA DA - 15.05.2016 KW - Niobium Carbide (NbC) KW - Friction KW - Wear PY - 2016 AN - OPUS4-36152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kloß, Heinz A1 - Woydt, Mathias T1 - Prediction of tribological limits in sliding contacts: flash temperature calculations in sliding contacts and material behavior N2 - In order to achieve greater efficiency or to meet light weight requirements, components are downsized. This, however, increases the load, e.g., Hertzian or nominal contact pressures and stresses of tribosystems. This load is expressed as pₐ·v-value, the product of nominal contact pressure and sliding velocity. pₐ·v-values are an effective tool for design engineers for predicting low wear/high wear transitions. Therefore, in the present work, topographical analysis has been combined with the plasticity of micro-asperities and the flash temperatures to estimate the limits of pₐ·v diagrams. The central piece of this set of models presented here is the calculations for flash temperatures and contact mechanics of micro-asperities. This central piece is used to predict the performance of materials in high velocity (turbines, machinery) and low velocity (human joint) applications. It is shown that the model combination suggested here is a useful tool for screening and preselecting a candidate and new materials with respect to tribological requirements before engaging in expensive testing. KW - Hot spot KW - Flash temperature KW - Micro-asperity KW - Abrasive wear KW - Turbine KW - Artificial hip joint KW - Low wear/high wear transition PY - 2016 DO - https://doi.org/10.1115/1.4033132 SN - 0742-4787 SN - 1528-8897 VL - 138 IS - 3 SP - 031403-1 EP - 031403-11 PB - The American Society of Mechanical Engineers AN - OPUS4-36122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burbank, John A1 - Woydt, Mathias T1 - Friction and wear reductions in slip-rolling steel contacts through pre-conditioned chemical tribofilms from bismuth compounds N2 - Downsizing in mechanical systems requires effective lubrication strategies to ensure that increased contact stresses do not cause critical material failure during operation. Additionally, eco-toxicological consideration are becoming increasingly important. In this regard, the goal of this investigation is to transfer the running-in phase into the final step of the mechanical finishing process through the targeted pre-conditioning of novel, high toughness steel bearings without thermo-chemical treatments and compare these to conventional, case-hardened Steels. Pre-conditioning involved implementation of the ecologically sustainable, bismuth-based additives to generate chemically reactive tribofilms on slip-rolling contacts by using a formulation with a high concentration of tribofilm forming additive. Generated tribofilms were analyzed by Raman spectroscopy to elucidate their molecular composition and, ultimately, determine the reaction mechanisms of bismuth-based tribofilm formation. Tribofilm-protected samples were subjected to slip-rolling endurance testing in a factory fill engine oil without pre-conditioning additives to determine the influence of pre-condition tribofilms on friction behavior and wear performance. It was observed that pre-conditioned tribofilms from the bismuth-based additives were able to yield lower coefficients of friction (COF) and profilometric wear coefficients than for Steels without pre-conditioning. Moreover, COF values under mixed/boundary conditions approaching and even less than 0.04 were achieved, thereby rivaling DLC-coated alloy equivalents. KW - tribofilm KW - bismuth KW - carbamate KW - slip-rolling KW - friction KW - wear PY - 2016 DO - https://doi.org/doi:10.1016/j.wear.2016.04.004 SN - 0043-1648 VL - 360-361 SP - 29 EP - 37 PB - Elsevier B.V. AN - OPUS4-35919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Woydt, Mathias ED - Czichos, Horst ED - Habig, K.-H. T1 - Hochtemperaturtribologie N2 - Die Temperatur ist eine fundamentale Beanspruchungs- bzw. Einflussgröße für alle tribologischen Systeme. Für die in zahlreichen tribologischen Systemen benötigten Schmierstoffe liegen die thermischen Stabilitätsgrenzen bei etwa 400?°C. Es wird die tribologische Prüftechnik für Tribomaterialien beschrieben, die für den Einsatz in tribologischen Systemen bei hohen Betriebstemperaturen verwendbar sind. Ausgehend von metallurgischen Lösungsansätzen aus der Tribologieforschung werden Anwendungsmöglichkeiten hochtemperaturbeständiger Ingenieurwerkstoffe mit Beispielen aus der Automobiltechnik (Luftlagerung von Turboladern, Leistungssteigerung von Bremsmaterialien), der Fertigungstechnik (Standzeitverlängerung von Werkzeugen) und dem chemischen Anlagenbau (Effizienzsteigerung von Kühlkreisläufen) dargestellt. PY - 2010 SN - 978-3-8348-1810-2 DO - https://doi.org/10.1007/978-3-8348-2236-9_18 SP - Kap. 18, 633 EP - 646 PB - Springer-Vieweg CY - Wiesbaden ET - 4. Auflage / 2015 AN - OPUS4-33840 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burbank, John Theodore A1 - Woydt, Mathias T1 - Friction and wear reductions under slip-rolling contact through chemically reactive tribofilm generation during pre-conditioning of steel alloys N2 - The running-in phase of mechanical systems is critical from a tribological standpoint, though poorly understood. Microcracks accelerate material failure and wear during this phase of heightened friction. With this in mind, the ultimate goal of this current work is to transfer the running-in phase into the final step of the mechanical finishing process through the targeted pre-conditioning of novel, high toughness steel bearings without thermo-chemical treatments and compare these to conventional, case-hardened steels. This pre-conditioning involved the targeted implementation of two specific lubricant packages, the first with CaCO3 as the active ingredient and the second with MoDTC as the active ingredient, to generate chemically reactive tribolayers (tribofilms) on twin disk testing rigs. Pre-conditioning was carried out up to 104 load cycles (approximately 25 min). The films generated in pre-conditioning were analyzed by SEM-EDX with Element-Mapping, Raman spectroscopy, and XPS to elucidate their molecular composition and concentration on the sample surfaces. The combination of these methods of analysis gave a clear indication that 104 cycles were sufficient to generate stable chemical tribofilms. CaO and CaCO3 were the main components of the tribofilm from the first lubricant package, while MoS2, MoO2 and MoO3 were the main components from the second lubricant package. Tribofilm-protected samples were then subjected to slip-rolling endurance testing (T=+120 °C, 10,000,000 cycles, approximately 19 days in a factory fill engine oil) to determine any changes in friction behavior or wear performance. Some significant reductions in coefficients of friction at the end of endurance testing were observed, though in certain cases, no definitive improvement was observed. In contrast, very strong reductions in wear were observed across the entire spectrum of materials and testing loads. In some cases, sample surface wear reduction from pre-conditioning via tribofilms reached over 90%. The observed improvements to friction behavior and wear performance are indicative of a technically simple, cost- and energy-efficient pre-conditioning method that may prove to be competitive with existing thermochemical treatments for steel alloys. KW - Tribofilm KW - Running-in KW - MoDTC KW - Slip-rolling KW - Friction KW - Wear PY - 2015 DO - https://doi.org/10.1016/j.wear.2015.06.006 SN - 0043-1648 VL - 338-339 SP - 133 EP - 143 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-33556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Slip-rolling Resistance of Alternative Steels under High Contact Pressures in Engine Oils T2 - ASTM 10. International Symposium on Advances in Steel Technologies for Rolling Bearings CY - Toronto, Canada DA - 2014-05-06 PY - 2014 AN - OPUS4-30598 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The use of niobium carbide (Nbc) for wear resistant tribosystems and the tribological backgrounds as cutting tools N2 - The tribological profile of rotating disks made in binder-less niobium Carbide (hot-pressed NbC) and cobalt-bonded NbCs (NbC-8Co and NbC-12Co) mated against alumina (99.7%) were determined under unidirectional sliding tests (0.1 m/s to 8.0 m/s; 22°C and 400°C) as well as in oscillation tests (f= 20 Hz, Ax= 0.2 mm, 2/50/98% rel. humidity, n= 105/l 06 cycles) under unlubricated (dry) conditions. In addition, the microstructure and mechanical properties of HPNbCl and NbC bonded with 8 vol.-% and 12 vol.-% cobalt were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where the NbCs bonded with 8% and 12% Co presented above 7 m/s the lowest wear rates so far in such a bench mark. HP-NbCl, NbC-8Co and NbC-12Co exhibited low wear rates under dry sliding associated with PV high load carrying capacities. The tribological profile established revealed a strong position of NbC bearing materials under tribological considerations and for closed tribo-systems against traditional references. T2 - 9th International conference on tungsten, refractory & hardmaterials CY - Orlando, FL, USA DA - 18.05.2014 KW - Friction KW - Wear KW - Ceramic KW - Oscillation KW - NbC KW - Niobium carbide KW - Cobalt KW - Hard metal KW - Strength KW - Sliding KW - Modulus KW - High temperatures PY - 2014 SN - 978-0-9853397-7-7 SP - 222 EP - 232 AN - OPUS4-31630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burbank, John Theodore A1 - Woydt, Mathias T1 - Reaktive Grenzschichten in metallischen Wälzkontakten N2 - Die Ausbildung von tribologisch günstigen Grenzschichten ist eine häufig für die Phase des Einlaufs angenommene Modellvorstellung. Solche tribologisch günstige, durch Reibungsvorgänge im Kontaktbereich induzierte Triboschichten, werden in der Fachliteratur auch als sog. Beilby- und Cervovit-Schichten oder auch als Tribomutationen bezeichnet. Durch eine Vorkonditionierung mittels modifizierter Schmierstoffe oder durch Kaltverfestigung kann der Verschleiß in Wälzkontakten signifikant erniedrigt werden. Bislang ausgeblieben ist eine deutliche Reibungsminderung, aber es wurde keine Reibungserhöhung gemessen. Es waren die Ziele, mithilfe geeigneter Schmierstoffadditive in Verbindung mit dem Prozess des Kaltverfestigens durch das „Dichtwalzen“ (unter Hertz’schen Kontaktpressungen oberhalb von Pmax = 3,0 GPa), ohne Vorschädigung, eine metallurgische Veränderung zu erzielen und gleichzeitig durch einen induzierten Tribofilm geschützte Stahloberfläche zu erhalten, sodass thermochemische Behandlungen durch diese Konzepte einzeln oder kombiniert substituiert werden können. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 04/1 EP - 04/11 AN - OPUS4-31631 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - The use of niobium carbide (Nbc) for wear resistant tribosystems and the tribological backgrounds as cutting tools T2 - 9. Tungsten, Refractory & Hardmaterials Conference CY - Orlando, FL, USA DA - 2014-05-18 PY - 2014 AN - OPUS4-31560 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nakase, Takuya A1 - Kato, S. A1 - Sasaki, S. A1 - Woydt, Mathias T1 - Friction reduction effect of alternative lubricants for plasma electrolytic oxidation coating on AA6061-T6 N2 - Drei verschiedene Grundöltypen (Poly-a-Olefin, Polypropylenglykol und ungesättigte TMP-Ester) und diese Grundöle additiviert mit 2 verschiedenen Additiven (1 Gew.-% ZnDTP oder 1 Gew.-% Dibenzyldisulfid (DBDS)) wurden als Schmiermittel verwendet, um die tribologischen Eigenschaften eines durch plasma-elektrolytische Oxidation behandeltes AA6061-T6 in einem SRV-Tribometer (Toi = 80 °C, Fn = 50N, v = 50 Hz, 2 mm Hub, 2 Stunden) zu bestimmen. Das PPG und die TMP-Ester mit und ohne Additive hatten bessere Schmierfähigkeiten als der PAO. ZnDTP reduziert zwar den Verschleiß, aber erhöht in PAO und PPG die Reibung. Die ungesättigten TMP-Ester + 1 Gew% DBDS zeigten eine um 45% geringere Reibung als PAO + ZnDTP (Referenz) und die Reibung PPG + DBDS war immerhin 30% niedriger. N2 - 3 different base-stocks (poly-a-olefin, polypropylene glycol and unsaturated TMP ester) and these blended with 2 different additives (1wt% ZnDTP or 1wt% dibenzyl disulfide(DBDS)) were used as lubricants to evaluate the tribological properties of AA6061-T6 treated by means of plasma electrolytic oxidation in a SRV tribometer (Toi|=80 °C, Fn = 50N, v= 50 Hz, 2mm stroke, 2hrs). The base oils of PPG and the TMP-ester had better lubricities than the PAO with/without the additives. ZnDTP tend to reduce wear, but when added to PAO and PPG increased the friction. The unsaturated TMP-ester +1wt%DBDS showed 45% lower friction than PAO + ZnDTP (reference), whereas PPG + DBDS had 30% lower friction. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 42/1 EP - 42/11 AN - OPUS4-31580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tamura, T. A1 - Nakase, Takuya A1 - Hosohata, S. A1 - Kato, S. A1 - Woydt, Mathias A1 - Wäsche, Rolf A1 - Köhler, Norbert T1 - Zero wear and low friction under dry sliding N2 - In diesem Beitrag werden ungeschmierte Gleitpaarungen auf Basis von Oxidkeramik/DLC vorgestellt, bei denen die tribologischen Kenngrößen mehr oder weniger invariant von der Gleitgeschwindigkeit sind. Die DLC-Dünnschicht besteht aus einem bestimmten Verhältnis an sp2/sp3-hybridisiertem Kohlenstoff. Im Gegensatz zu artgleichen Gleitpaarungen aus MgO-.Zr02, AI2O3 oder SSiC mit Reibungszahlen oberhalb von 0,45, zeigt die Gleitpaarungen aus MgO-Zr02/DLC und alpha-A^OVDLC Festkörpergleitreibungszahlen zwischen 0,075 und 0,15, welche mit ansteigender Gleitgeschwindigkeit leicht abnahmen. Die Verschleißkoeffizienten der DLC-Dünnschichten lagen im Bereich von kleiner als 10~7 mm3/Nm bis herunter zu 10"9 mm3/Nm. N2 - This paper presents a dry sliding tribo-couple (DLC/monolithic oxide ceramics), where the tribological quantities are more or less in a wide ränge independent of the sliding speed. The DLC film is composed of a specific mixture of sp3 /sp2 hybridized carbon. Self-mated ceramic/ceramic couples of MgO-Zr02, alpha-AI203 or SSiC are with their coefficients of friction above 0.45 not so lubricious, whereas the coefficients of friction of the tribocouples MgO-Zr02/DLC and alpha-AbOVDLC ranged between 0.075 and 0.15 under dry sliding. The coefficients of friction for these tribo-couples tend to decrease with increase sliding speed from 0.03 m/s to 6 m/s. The dry wear rates of the thin film is low (<10‘7 mm3/Nm) and perfectly independent from sliding velocity. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 43/1 EP - 43/7 AN - OPUS4-31581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The tribological and mechanical properties of niobium carbides (NbC) bonded with cobalt of Fe3Al N2 - The tribological and mechanical properties of niobium carbide bonded with 8 vol.-% (NbC-8Co), 12 vol.-% of cobalt (NbC-12Co) or 12 vol.-% of Fe3Al (NbC-12Fe3Al) are presented. Rotating discs made of metal-bonded niobium carbide were mated against alumina (99.7%) under unlubricated (dry) unidirectional sliding tests (0.1 m/s to 12.0 m/s; 22 °C and 400 C) as well as in oscillation tests (f=20 Hz, Δx=0.2 mm, 2/50/98% rel. humidity, n=105/106 cycles). Microstructure and phase compositions were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where NbC bonded with 8% and 12% Co presented above 7 m/s the lowest wear rates so far in such a benchmark. Binderless NbC (HP-NbC1) and the metal-bonded NbCs exhibited low wear rates under dry sliding associated with P·V high load carrying capacities. NbC-based hard metal bonded with 12 vol.-% of Fe3Al resulted in a higher hardness level than for 12 vol.-% cobalt. The tribological profile established revealed a strong position of NbC-bearing materials under tribological considerations and for closed tribosystems against established reference tribo-couples. KW - Sliding KW - Ceramic KW - Oscillation KW - Strength KW - Modulus KW - High temperatures KW - Friction KW - Wear KW - NbC KW - Niobium carbide KW - Cobalt KW - Fe3Al KW - Hard metal PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316129 DO - https://doi.org/10.1016/j.wear.2014.09.007 SN - 0043-1648 VL - 321 SP - 1 EP - 7 PB - Elsevier CY - Amsterdam AN - OPUS4-31612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Adjusting the functional properties of niobium carbide N2 - The process window and range of functional properties of NbC is wide, because micro-hardness, hot hardness, sliding wear resistance, elastic modulus and toughness can be tailored by the C/Nb ratio, because Nb4C3, Nb6C5 and other short and long range ordered phases occur in the region of homogeneity of NbCx (0,75≤ x ≤1.0) in the binary Phase diagram, and by the type of binder. Further improvements enable the addition of secondary carbides. Supporting results from literature and different grades with varying C/Nb ratio or binder types were illuminated. Thus, the NbC system offers to producers a wider process window, than WC. The impact of these tailored properties on sliding wear and cutting performance was illuminated by tribological and machining results. NbC can be synthesized by carbothermal conversion of Nb2O5 or be metallurgically grown in melts and leached out as coarse NbC cubes. NbC provides comparably lower friction in many relevant tribo-contacts and displays low wear. NbC and Nb2O5 have so far no REACH classification related to human toxicology and are not listed as substances of very high concern contrary to WO3 and Co3O4. T2 - 2016 International Conference on Powder Metallurgy & Particulate Materials CY - Boston, MA, USA DA - 05.06.2016 KW - Niobium carbide KW - NbC KW - Wear KW - Friction PY - 2016 AN - OPUS4-36497 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Genga, R. M. A1 - Rokebrand, P. A1 - Cornish, L. A. A1 - Nelwalani, N. A1 - Brandt, Guido A1 - Kelling, Norbert A1 - Woydt, Mathias A1 - Janse van Vuuren, A. A1 - Polese, C. T1 - High-temperature sliding wear, elastic modulus and transverse rupture strength of Ni bonded NbC and WC cermets N2 - The effects of rapid pulse electric current sintering (PECS), substitution of WC by NbC and Co by Ni, and carbide additives (TiC and Mo2C) on the microstructure, elastic modulus, B3B transverse rupture strength (TRS) and high temperature sliding wear on WC-Co, WC-Ni, NbC-Co and NbC-Ni cermets were studied. High temperature sliding wear tests were carried out using a ball-on-disk tribometer, with a 10 N force, at a sliding speed of 1.34 m/s for 0.8 km (10 min) and 2.4 km (30 min), using 100Cr6 (AISI 52100) steel balls at 400 °C and 0% humidity. Additions of TiC and Mo2C to NbC-12Ni improved the sliding wear resistance, with TiC having the greater effect, reducing the sample wear rate by over 30% from 15.1×10−6mm3/N·m to 9.4×10−6mm3/N·m after sliding distance of 2.4 km. Generally, the LPS samples had lower wear volumes than the corresponding SPS samples, due to higher K1c and TRS. KW - Pulse electric current sintering KW - Niobium carbide KW - Nickel KW - Molybdenum carbide KW - Titanium carbide PY - 2020 DO - https://doi.org/10.1016/j.ijrmhm.2019.105143 SN - 0263-4368 VL - 87 SP - 105143 PB - Elsevier Ltd. AN - OPUS4-51473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Scholz, C. A1 - Burbank, J. A1 - Spaltmann, Dirk T1 - Slip-rolling resistant steel alloys up to P0max of 3,920 MPa N2 - Downsizing (power-to-weight ratio) and higher speeds lead to a rise in Hertzian contact pressures in combination with an increase in surface or oil temperatures. Under such conditions, commonly used bearing steels, such as 100Cr6, reach their limits, creating a demand for alternative slip-rolling resistant steel alloys. The present work therefore compares the slip-rolling performance of various steel types with Maraging- and PM-type steel alloys such as e.g. CSS-42L™, ASP2012, BIMAX42+, in the Hertzian contact pressure range up to P0max of 4 GPa. Through-hardened 100Cr6H (AISI 52100), case-hardened 20MnCr5 (AISI 5120H) and nitrogen alloyed Croni-dur30 (AMS 5898) still compete in terms of slip-rolling and wear resistance and load carrying capacity, whereas Maraging- and PM-type steel alloys offer superior strength and toughness properties. KW - Steel KW - Alloy KW - Slip-rolling KW - Friction KW - Wear rate KW - Contact pressure KW - 100Cr6 KW - BIMAX42 KW - CSS-42L KW - ASP20212 PY - 2012 DO - https://doi.org/10.1016/j.wear.2021.203707 VL - 474-475 SP - 203707 PB - Elsevier B.V. AN - OPUS4-52549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tribological profile of hydraulic oils by using SRV N2 - Hydraulic oils are well established formulations developed around the pump test. Requirements for energy efficiency and also environmentally acceptable properties increased the demand for development. In the same time, system pressure and the used of servo-hydraulic vanes increased bringing specific formulations and materials to their limit. The vane pump is a key component in hydraulic systems and many other tribosystems in hydraulic circuits operate under different tribological operating conditions. The concept for ranking of hydraulic oils consists in using existing SRV-based ASTM test methods for evaluation of friction, wear and extreme pressure properties: D6425, friction and wear of oils (homologue to DIN 51834-2), D7421, extreme pressure properties of oils and D7755, wear volumes of ball and disks (homologue to DIN 51834-3. The tribological properties are assessed under the regime of mixed/boundary lubrication The SRV-based concept of tribological profile generates the wear volumes on two triboelements (specimen) and the extreme pressure properties as well as the evolution of friction in the wear and extreme pressure load step test. Thus, the benchmark and validation of hydraulic oils bear on a wider range of tribological properties. Round robin test results using the aforementioned testing concept will be shown. Another outcome is tribological set limits for inclusion in hydrau¬lic oil speci¬fications. T2 - Workshop on Tribological Testing of Components Using the SRV Test Machine CY - Bellevue, WA, USA DA - 30.06.2016 KW - Tribology KW - Hydraulic oils KW - SRV KW - ASTM test method KW - Friction KW - Wear PY - 2016 AN - OPUS4-36734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - The identification in engine or gear tests of the induction time or off-set point („cliff“), after which wear and friction increased N2 - In the state-of-the-art technology, the impact of additives on friction and wear is evaluated in recipes with fixed concentrations. For the development of formulations it is desirable to determine the lowest effective concentration or the concentration at which failure was initiated or excessive wear began. Through a new development of the SRV® machine it is now possible to change the lubricant composition of a test specimen in a reproducible manner, in sub-pro Mill steps during the SRV® testing. This technology is used in the present article to define the optimum additive concentration with regard to wear and friction in a system of base oil and additive. Exemplary selected base oil and additive variants are tested here. The load parameters during testing are selected in such a way that they correspond to later application. The new data acquisition capabilities enable new possibilities for optimizing lubricant formulations in practice-oriented model-tribometer tests. “Cliff“ testing aims to identify in engine or gear tests the induction time or off-set point (“cliff“) after which wear and friction increased of failure occurred. Explanations for friction and wear increased as well as failures, which occurred during engine tests, can be derived from SRV® testing of oil samples taken or collected at different engine test times and correlating these with their friction, wear and EP data in respect to depleting curves for specific additives or other oil properties. A “cause-root” analysis is done by plotting SRV® data versus functional properties. The collected oil samples must be fully SRV® tested and chemically analyzed. T2 - Workshop on Tribological Testing of Components Using the SRV Test Machine CY - Bellevue, WA, USA DA - 30.06.2016 KW - Cliff testing KW - Additives KW - SRV machine KW - Friction KW - Wear behavior PY - 2016 AN - OPUS4-36743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. A1 - Vleugels, J. A1 - Huang, S. T1 - Substitution of tungsten carbide by niobium carbide as cutting materials and for wear protection N2 - Im binären System NbC-C existieren verschiedene Phasen im Homogenitätsbereich NbCₓ, mit 0,75 ≤ x ≤ 1,0, wie NbC, Nb₆C₅ und Nb₄ C₃ , die ein breites Prozessfenster beim Sintern und in der Werkstoffentwicklung ermöglichen. Die Mikrohärte, die Warmhärte, der Verschleißwiderstand, das Elastizitätsmodul und die Zähigkeit von Hartmetallen hängen vom C/Nb-Verhältnis ab, wie auch von der Zugabe von Sekundärcarbiden. N2 - Several phases, like Nb₄ C₃ , Nb₆C₅ and other short and long range ordered phases occur in the region of homogeneity of NbCₓ (0.75 ≤ x ≤ 1.0) in the binary phase diagram. Properties, like micro-hardness, hot hardness, sliding wear resistance, elastic modulus and toughness can be tailored by the C/Nb ratio, the addition of secondary carbides and the type of binder. Supporting results from different grades with varying C/Nb ratio or binder types were illuminated. Thus, the NbC system offers to producers a wider process window, than WC. The impact of these tailored properties on sliding wear and cutting performance was illuminated by tribological and machining results. Niobium is today largely available. NbC can be synthesized by carbothermal conversion of Nb₂O₅ or be metallurgically grown and leached out, provides comparably low friction in many relevant tribo-contacts and displays low wear. NbC and Nb₂O₅ have so far no REACH classification related to human toxicology and are not listed as substances of very high concern contrary to WO₃ and Co₃ O₄ . T2 - 57. Tribologie-Fachtagung CY - Göttingen, Germany DA - 26.09.2016 KW - cutting materials KW - niobium carbide KW - wear protection PY - 2016 SN - 978-3-9817451-1-5 SP - 65/1 EP - 65/14 AN - OPUS4-37833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tribology in hot steam - for waste heat recovery or for energy harvesting - N2 - The wear rates of self-amted alumina couples show that friction as well as wear is largely determined by the above mentioned hydro-thermal conditions. The presence of water and ist amount available in the surrounding system either in liquid or in gaseous from plays a key role for friction and wear behavior and cabe benefical for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2, alumina and antimony impregnated carbon. T2 - 21th International Colloquium Tribology CY - Stuttgart/Ostfildern, Germany DA - 09.01.2018 KW - Friction KW - Alumina KW - Hot steam PY - 2018 AN - OPUS4-43895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Wäsche, Rolf A1 - Brandt, Guido A1 - Ehrke, Roman A1 - Yano, S. A1 - Sasaki, S. T1 - Tribology in hot steam for energy recovery N2 - The wear rates of self-mated alumina couples show that friction as well as wear is largely determined by the above-mentioned hydro-thermal conditions. The presence of water and its amount available in the surrounding system either in liquid or in gaseous form plays a key role for friction and wear behavior and can be beneficial for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2 alumina and antimony impregnated carbon. T2 - 21th International Colloquium Tribology CY - Stuttgart/Ostfildern, Germany DA - 09.01.2018 KW - Tribology KW - Friction KW - Alumina KW - Hot steam PY - 2018 SP - 1 EP - 2 AN - OPUS4-43896 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spaltmann, Dirk A1 - Woydt, Mathias T1 - An alternative approach to simulating an entire particle erosion experiment N2 - In the present work an approach is presented which combines various aspects of the former models with probability considerations. It is used to simulate the impact of more than one billion Alumina particles onto a steel substrate. This approach permits the simulation of an entire erosion experiment on an average PC within about six hours. KW - Particle erosion KW - Wear KW - DEM KW - FEM KW - Monte-Carlo simulation KW - Alumina PY - 2018 DO - https://doi.org/10.3390/lubricants6010029 VL - 6 IS - 29 SP - 1 EP - 11 PB - MDPI AN - OPUS4-44542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Huang, S. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Cannizza, E. T1 - Potentials of niobium carbide (NbC) as cutting tools and for wear protection N2 - Research and development of WC grades is 90 years ahead of niobium carbide-based hard materials, which showed already as light-weight and unexplored material a very high potential for many technical applications, especially for wear protection and machining. NbC evoluted recently from lab scale to pilot scale, especially in areas where established WC-based materials are causing economic, environmental or technical concerns. Benchmark trials of NbC-based hard metals indicated already a favorable performance in machining of steel components. KW - Niobium carbide KW - Friction KW - Wear KW - NbC KW - Hard metals KW - Machining KW - Nickel PY - 2018 DO - https://doi.org/10.1016/j.ijrmhm.2018.01.009 SN - 0263-4368 VL - 72 SP - 380 EP - 387 PB - Elsevier Ltd. AN - OPUS4-44166 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The tribological property profile of hard metals and metal matrix composites based on niobium carbide N2 - This work is focused on the tribological profile of NbC-based material, as well as their potential applications and environmental implications. T2 - International Symposium on Wear Resistant Alloys for the Mining and Processing Industry CY - Sao Paulo, Brazil DA - 04.05.2015 KW - Niobium carbide KW - Metal KW - Binder KW - Metal matrix composite KW - Friction KW - Wear KW - Hardness KW - Solubility KW - Toughness KW - Abrasion PY - 2018 SN - 978-0-692-05382-9 SP - 427 EP - 461 AN - OPUS4-44201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - NbC-based cermets: influence of secondary carbide addition and metal binder N2 - Full densification of Fe, Co and Ni bonded NbC based cermet’s was achieved by pressure less liquid phase sintering in vacuum for one hour at 1420°C. The hardness and toughness of the NbC matrix cermet’s can be mainly tailored by the binder composition and secondary carbide additions. Ni binder based NbC cermet’s allow the combination of high hardness and improved toughness. The addition of lesser amounts of VC/Cr3C2 in a NbC partially substituted WC-Co cemented carbide increased significantly the hardness in combination with a moderate fracture toughness. T2 - International Symposium on Wear Resistant Alloys for the Mining and Processing Industry CY - Sao Paulo, Brazil DA - 04.05.2015 KW - Niobium carbide KW - Hardmetal KW - Cemented carbide KW - Sintering KW - Grain growth KW - Microstructure KW - Hardness KW - Fracture toughness PY - 2018 SN - 978-0-692-05382-9 SP - 521 EP - 534 AN - OPUS4-44206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le Quilliec, G. A1 - Leroy, R. A1 - Richard, C. A1 - Woydt, Mathias A1 - Morandeau, A. T1 - Comparison of the life-span of NbC-Co and WC-Co inserts during different machining operations on 100Cr6 (SAE 52100) bearing steel N2 - The aim of the study presented in this paper is to highlight the potential of niobium carbide cutting tool inserts for machining and to compare their performance to commercially available tungsten carbide inserts. In this work, a comparison between a conventional Wc-Co insert and NbC-Co inserts was carried out under hard machining conditions on specimens made of 100Cr6 bearing steel grade (SAE 52100). T2 - International Symposium on Wear Resistant Alloys for the Mining and Processing Industry CY - Sao Paulo, Brazil DA - 04.05.2015 KW - Niobium carbide KW - Cobalt KW - Fe3Al KW - Inserts KW - Cutting tools KW - Wear KW - Turning PY - 2018 SN - 978-0-692-05382-9 SP - 535 EP - 545 AN - OPUS4-44207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Genga, R. M. A1 - Cornish, L. A. A1 - Woydt, Mathias A1 - Sobiyi, K. A1 - Polese, C. T1 - Wear and Mechanical properties of spark plasma and liquid phase sintered WC and NbC based cemented carbide inserts N2 - The effects on the mechanical properties, thermal behavior, response to cutting forces and wear mechanisms have been investigated for different manufacturing processes and materials for cemented carbide inserts. T2 - International Symposium on Wear Resistant Alloys for the Mining and Processing Industry CY - Sao Paulo, Brazil DA - 04.05.2015 KW - WC KW - NbC KW - SPS KW - Co KW - Fe3Al KW - Hard-turning KW - Interrupted milling KW - Flank KW - Wear KW - Coolant-free KW - Crater wear KW - Machinability PY - 2018 SN - 978-0-692-05382-9 SP - 547 EP - 567 AN - OPUS4-44208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S. A1 - De Beats, P. A1 - Sukumaran, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias A1 - Vleugels, J. T1 - Effect of carbon content on the microstructure and mechanical properties of NbC-Ni based cermets N2 - The aim of this work was to correlate the overall carbon contents in NbC-Ni, NbC-Ni-VC and NbC-Ni-Mo starting powders with the resulting microstructure, hardness, and fracture toughness of Ni-bonded NbC cermets. KW - Niobium carbide KW - Cermet KW - Hardmetal KW - Liquid phase sintering KW - Carbon KW - Hardness PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444608 DO - https://doi.org/10.3390/met8030178 SN - 2075-4701 VL - 8 IS - 3 SP - Article 178, 1 EP - 13 PB - MDPI AN - OPUS4-44460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Uhlmann, E. A1 - Kropidlowski, K. A1 - Hinzmann, D. A1 - Meier, P. A1 - Prasol, L. A1 - Woydt, Mathias T1 - Drehen mit Niobcarbid-basierten Werkzeugen N2 - Niobcarbid (NbC) stellt aufgrund vorteilhafter Eigenschaften, wie zum Beispiel eine geringe Diffusionsneigung, in der Zerspannung eine vielversprechende Alternative zu konventionellen Schneidstoffen wie Wolframcarbid (WC) dar. Als Substitution der Hartstoff-Phase WC im Hartmetall wird NbC in der trockenen Drehbearbeitung von eisen-basierten Werkstoffen untersucht. Diesbezüglich wurden zwei NbC-Substrate mit WC hinsichtlich ihres Werkzeugverschleißes quantitativ verglichen. Im Gegensatz zu WC-Werkzeugen wird das Potential von NbC bei zunehmender Schnittgeschwindigkeit vc durch eine steigende Prozessstabilität deutlich. KW - Niobcarbid (NbC) KW - Werkzeug KW - Verschleiß PY - 2018 UR - https://www.werkstattstechnik.de/wt/article.php?data[article_id]=88885 SN - 1436-4980 SN - 1436-5006 VL - 108 IS - 1/2 SP - 18 EP - 25 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-44448 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Brandt, Guido A1 - Ehrke, Roman A1 - Nolze, Gert A1 - Schmid, Thomas A1 - Sasaki, S. A1 - Woydt, Mathias T1 - Wear behaviour of alpha-alumina in hot steam at high contact pressure N2 - The work examines the wear behaviour of α-aluminium oxide by combining thermodynamic modelling with advanced wear testing as well as analytical methods to get a better understanding of this structural ceramic material wear behavior and its possible use in high temperature steam environment. KW - Aluminium oxide KW - Temperature KW - Hot steam KW - Diaspore KW - Ceramic KW - Wear PY - 2018 DO - https://doi.org/10.1016/j.wear.2018.02.012 SN - 0043-1648 SN - 1873-2577 VL - 404-405 SP - 22 EP - 30 PB - Elsevier B.V. AN - OPUS4-44449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Genga, R. M. A1 - Cornish, L. A. A1 - Woydt, Mathias A1 - Janse van Vuuren, A. A1 - Polese, C. T1 - Microstructure, mechanical and machining properties of LPS and SPS NbC cemented carbides for face-milling of grey cast iron N2 - The effects of spark plasma sintering (SPS), NbC as a major carbide phase and Ni as a Co binder substitute on the microstructure, mechanical properties and cutting insert wear during face-milling of grey cast iron (GCI) BS1452, grade 17, were investigated. KW - Niobium carbide KW - NbC KW - Hardness KW - Wear PY - 2018 DO - https://doi.org/10.1016/j.ijrmhm.2017.12.036 SN - 0263-4368 VL - 73 SP - 111 EP - 120 PB - Elsevier Ltd. AN - OPUS4-44083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kovalev, A. A1 - Spaltmann, Dirk A1 - Woydt, Mathias A1 - Meng, Y. T1 - Characterization of low wear on top aperities N2 - The aim of this research is to characterize a surface that has experienced low wear on asperities. The procedure used is similar to an Abbott-Firestone approach and based on functional bearing of projected area, surface area and material volume. Surface features extracted from surface height maps provide more comprehensive information about topography changes due to wear. Thus, they were used to detect low wear volumes on the top of asperities. T2 - The 6th World Tribology Congress CY - Beijing, China DA - 17.09.2017 KW - Simulation KW - Wear KW - Asperities KW - Abbott KW - Firestone PY - 2017 SP - 1 EP - 4 AN - OPUS4-42465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tribology in hot steam - for waste heat recovery or for energy harvesting - N2 - The wear rates of self-mated alumina couples show that friction as well as wear is largely determined by the above mentioned hydro-thermal conditions. The presence of water and its amount available in the surrounding system either in liquid or in gaseous form plays a key role for friction and wear behavior and can be beneficial for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2, alumina and antimony impregnated carbon. T2 - The 6th World Tribology Congress - WTC 2017 CY - Beijing, China DA - 17.09.2017 KW - Hot steam KW - Friction KW - Wear behavior PY - 2017 AN - OPUS4-42471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias ED - Wäsche, Rolf ED - Brandt, Guido ED - Ehrke, Roman ED - Yano, S. ED - Sasaki, S. T1 - Tribology in hot steam N2 - The wear rates of self-mated alumina couples show that friction as well as wear is largely determined by the above mentioned hydro-thermal conditions. The presence of water and its amount available in the surrounding system either in liquid or in gaseous form plays a key role for friction and wear behavior and can be beneficial for the tribological profile of steam degradation resistant materials. Hot steam enhances the tribo-chemical formations of oxides and hydroxides on MgO-ZrO2, alumina and antimony impregnated carbon. T2 - The 6th World Tribology Congress CY - Beijing, China DA - 17.09.2017 KW - Hot steam KW - Friction KW - Wear behaviour PY - 2017 SP - 1 EP - 3 AN - OPUS4-42472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Status of nickel bonded niobium carbide (NbC) as a substitute for cobalt bonded tungsten carbide (WC) as cutting tools and for wear protection N2 - The research and developments on niobium carbide-based hard materials generated grades, which meet the application line for tungsten carbide and showed already a very high potential for many technical applications, especially for wear protection and machining. T2 - The 6th World Tribology Congress - WTC 2017 CY - Beijing, China DA - 17.09.2017 KW - Niobium carbide KW - NbC KW - Cutting tools PY - 2017 AN - OPUS4-42473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias ED - Huang, S. ED - Vleugels, J. ED - Mohrbacher, H. T1 - Cutting tools and wear protection through nickel bonded niobium carbide (NbC) as a subtitute for cobalt bonded tungsten carbide (WC) N2 - The research and developments on niobium carbide-based hard materials generated grades, which meet the application line for tungsten carbide and showed already a very high potential for many technical applications, especially for wear protection and machining. T2 - The 6th World Tribology Congress - WTC 2017 CY - Beijing, China DA - 17.09.2017 KW - Cutting tools KW - Niobium carbide KW - NbC PY - 2017 SP - 1 EP - 4 AN - OPUS4-42474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spaltmann, Dirk A1 - Woydt, Mathias T1 - Alternative approach to simulate an entire particle erosion experiment N2 - The cause and type of solid particle erosion varies across different industries and locations in plants, for instance the particles could be volcanic ash in aero-engines, fly ash in boilers, exfoliated scale in steam turbines or mineral matter in oil excavation. In all cases the durability of materials can be improved through better surface engineering and coatings, but the development of these is restricted also due to lack of generic models. In this respect, the simulation of a single impact with finite element methods using 100.000 knots would take about 15 minutes. In order to simulate an entire particle erosion experiment, up to one billion of such impacts would have to be considered. In order to simulate an entire particle erosion experiment, the current work presents an alternative approach capable of calculating about half a billion impacts on a substrate in less than six hours on a standard PC. The predictions of the simulation will be compared to a steel sample at 600°C eroded by aluminum oxide particles with a velocity around 210 m/s. T2 - The 6th World Tribology Congress CY - Beijing, China DA - 17.09.2017 KW - Particle erosion KW - Simulation KW - Wear PY - 2017 SP - 1 EP - 3 AN - OPUS4-42449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Uhlmann, E. A1 - Hinzmann, D. A1 - Kropidlowski, K. A1 - Meier, P. A1 - Prasol, L. A1 - Woydt, Mathias T1 - Substitution of commercially coated tungsten carbide tools in dry cylindrical turning process by HiPIMS coated niobium carbide cutting inserts N2 - In this study the tool behavior of two NbC substrates, defined as NbC0.88-12Co and NbC1.0-12Ni4Mo4VC respectively, is compared to commercial, submicron grained WC-6Co tool material. KW - Turning KW - Tool KW - Coating KW - Physical vapor deposition (PVD) KW - Niobium carbide (NbC) PY - 2018 DO - https://doi.org/10.1016/j.surfcoat.2018.07.105 SN - 0257-8972 VL - 354 SP - 112 EP - 118 PB - Elsevier AN - OPUS4-45963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Dry turning with niobium carbide based tools N2 - Niobium carbide (NbC) has attracted recently some attention as a substitute for tungsten carbide in machining. In the present work it was shown that the metallurgical and mechanical aspects favoring long tool lifes of NbC. T2 - POWDERMET 2018 CY - San Antonio, TX, USA DA - 17.06.2018 KW - Niobium carbide KW - NbC KW - Cutting tool KW - Machining PY - 2018 SN - 978-1-943694-18-1 VL - 2 SP - 538 EP - 545 AN - OPUS4-45802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wägner, Yannick A1 - Binkowski, Sigrid A1 - Woydt, Mathias T1 - Charakterisierung von Hartstoffphasen in Gefüge N2 - Der Beitrag handelt von der Verbesserung der Verschleißbeständigkeit von Hartstoffphasen in Metal Matrix Composites (MMC), Hartgusslegierungen, Hadfield-Stählen oder Werkzeugstählen. T2 - 15. International Metallographie-Tagung CY - Leoben, Asutria DA - 19.09.2018 KW - Verschleißbeständigkeit KW - Hartstoffphasen KW - NbC PY - 2018 SN - 978-3-88355-416-7 VL - 52 SP - 133 EP - 138 PB - DGM - INVENTUM GmbH CY - Sankt Augustin AN - OPUS4-46056 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Burbank, J.-Th. A1 - Spaltmann, Dirk T1 - Generation of defined tribofilms and their stability under slip-rolling in a 2disk test rig N2 - In the present work it was shown that the performance of tribofilms which were generated in 2Disk test rigs on widely used reference steels during slip-rolling in the mixed/boundary lubrication regime at 120°C is compared to those created on alternative steels. KW - slip-rolling KW - 2Disk KW - friction KW - wear KW - tribofilms KW - additive KW - test method PY - 2018 DO - https://doi.org/10.1520/MPC20170078 SN - 2379-1365 SN - 2165-3992 VL - 7 IS - 3 SP - 213 EP - 225 PB - ASTM International CY - West Conshohocken, Pa. AN - OPUS4-46304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Habig, K.-H. A1 - Woydt, Mathias ED - Grote, K.-H. ED - Bender, B. ED - Göhlich, D. T1 - E5 Tribologie N2 - Das Nachschlagewerk für Studium und Beruf umfasst den gesamten Maschinenbau und seine Randgebiete. Das Kapitel Tribologie umfasst die Teilgebiete Reibung, Verschleiß und Schmierung. KW - Tribologie KW - Reibung KW - Verschleiß KW - Schmierung KW - Nachschlagewerk PY - 2018 SN - 978-3-662-54805-9 DO - https://doi.org/10.1007/978-3-662-54805-9_38 SP - E 90 EP - E 98 PB - Springer-Verlag gmbH Deutschland CY - Berlin, Heidelberg ET - 25 AN - OPUS4-46275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Scenarios and new technologies for complying with CO2 regulations - the contribution of lubricants - N2 - The present work deals with lubricants for mobility. T2 - Automechanika: Symposium "The Vital Lubricants" CY - Frankfurt/Main, Germany DA - 12.09.2018 KW - Lubricants KW - New technologies KW - Fuel economy KW - Mobility PY - 2018 AN - OPUS4-46215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - Effect of Ti(C0.7N0.3) content on the microstructure and mechanical properties of Ni bonded NbC-Ti(C0.7N0.3) based cermets N2 - In the present work it was shown that the addition of VC or a combination of VC + Ti(C0.7N0.3) was efficient in reducing the NbC grain growth during liquid phase sintering, when compared to NbC-Ni equivalents. A finest NbC grain size of 1.48 µm was obtained in the NbC-15 Ti(C0.7N0.3)-10 Ni-7.5 VC cermet, exhibiting a hardness of 1486 +/- 7 kg/mm2 and a fracture toughness of 8.7 +/- 0.1 MPa m 1/2. KW - Cermet KW - Niobium carbide KW - Carbonitride KW - Sintering KW - Mechanical properties PY - 2018 DO - https://doi.org/10.4028/www.scientific.net/SSP.274.43 SN - 1662-9779 VL - 274 SP - 43 EP - 52 PB - Trans Tech Publ. CY - Uetikon AN - OPUS4-44962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Dry turning with niobium carbide based tools N2 - The performance of straight and uncoated NbC grades under dry machining of 100Cr6 (SAE 52100), X90CrMoV18 (AISI 440B), 42CrMoV4 Q&T (AISI 4140), C45E (SAE 1045H) and grey cast iron GG35 in comparison to commercially available WC-xxCO and WC-xxCo-zMeC grades will be summarized. T2 - International Conference on Powder Metallurgy & Particulate Materials (POWDERMET 2018) CY - San Antonio, TX, USA DA - 17.06.2018 KW - Niobium carbide KW - Cutting tools KW - Hardness PY - 2018 AN - OPUS4-45389 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Scenarios and new technologies for complying with CO2 regulations N2 - Metallurgy and Tribology offer different novel tools for meeting fuel economy targets. Each of metallurgy, coatings, additives and base oils promote itself as exclusively blessed way to assure fuel economy. It is likely, that two, three or all generate the bigger fuel economy benefits and make the team working difficult for the OEM. Metallurgy and Tribology enables the implementation of new technologies for waste heat recovery, like hot steam. In consequence, multi-disciplinary co-engineering needs to be established. Finally, this is the most promising way, but people dislike changes. Embargo and dual use regulations limits the global availability of thin films and also some alternative steels. T2 - IEA-AMT Technical Symposium CY - Berlin, Germany DA - 31.05.2018 KW - Fuel economy KW - Alternative fuels KW - Heat recovery PY - 2018 AN - OPUS4-45105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - Microstructure and mechanical properties of NbC matrix cermets using Ni containing metal binder N2 - The current study reports on the effect of the addition of Al metal and secondary refractory carbides on the microstructure and mechanical properties of Ni bonded NbC matrix cermets. KW - NbC KW - Niobium carbide KW - Hardness KW - Hard materials PY - 2016 DO - https://doi.org/10.1016/j.mprp.2016.05.009 VL - 71 IS - 5 SP - 349 EP - 355 PB - Elsevier Ltd. AN - OPUS4-44623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. A1 - Vleugels, J. A1 - Huang, S. T1 - Potentials of niobium carbide (NBC) as cutting tools and for wear protection N2 - Niobium is today largely available. NbC displayed lower dry sliding friction over WC grades. The softer Ni- and NiMo-bonded NbC1.0-grades have a higer abrasive wear resistance (ASTM G65), even with lower toughnesses, than the tougher WC-Co grades and harder NbC-Co grades. T2 - 41st International Conference and Exposition on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 22.01.2017 KW - Niobium Carbide (NbC) KW - Cutting tool KW - Hardness KW - Friction PY - 2017 VL - 38 SP - 1 EP - 13 AN - OPUS4-43430 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Czichos, Horst A1 - Woydt, Mathias ED - Totten, George E. T1 - Introduction to tribology and tribological parameters N2 - Content: Research and Testing. Structural Parameters. Operational Parameters. Contact Parameters. Friction Parameters. Wear Parameters. Material Parameters and Selection. Appendix: Principles of General System Theory. KW - Tribology KW - Tribological parameters KW - Wear KW - Friction PY - 2017 SN - 978-1-62708-141-2 VL - 18: Friction, Lubrication, and Wear Technology SP - 2 EP - 14 CY - Materials Park, OH, USA AN - OPUS4-43589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Czichos, Horst A1 - Woydt, Mathias ED - Totten, George E. T1 - Tribological testing and presentation of data N2 - Content: Research and Testing. Machinery or Component-Level Tests. Laboratory and Specimen Testing. Laboratory Friction and Wear Tests. Investigation of Worn Surfaces. Presentation of Friction and Wear Data. Transition Diagrams. Tribomaps. Wear Data and Reliability. KW - Metals KW - Tribology KW - Friction KW - Wear PY - 2017 SN - 978-1-62708-141-2 VL - 18: Friction, Lubrication, and Wear Technology SP - 16 EP - 32 CY - Materials Park, OH, USA AN - OPUS4-43592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - NbC grain growth control and mechanical properties of Ni bonded NbC cermets prepared by vacuum liquid phase sintering N2 - The current study reports on the effect of the sintering temperature and secondary carbide (VC, Mo2C and TiC) and Mo additions on the NbC grain growth, microstructure evolution as well as concomitant Vickers hardness (HV30) and fracture toughness of Ni-bonded NbC cermets. KW - Cermet KW - Niobium carbide KW - Sintering KW - Microstructure KW - Mechanical properties PY - 2018 DO - https://doi.org/10.1016/j.ijrmhm.2017.12.013 SN - 0263-4368 VL - 72 SP - 63 EP - 70 PB - Elsevier Science CY - Amsterdam AN - OPUS4-43582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Cutting tool materials niobium carbide (NbC) substituting tungsten carbide and cermets N2 - The present paper illuminates the metallurgical progress on niobium carbide based hard metal developments, which are characterized by: a.) the substitution of cobalt binder by nickel, b.) the change from SPS to conventional sintering and c.) by switching from lab to pilot scale. The toughness was increased in the frame of these developments without loosening the hardness level. The hardness-toughness profile of NbC grades match those of WC and cermet grades. Apart from the aforementioned parameters, the properties depend from the powder processing and sintering conditions. The functional profile of nickel and NiMo bonded NbC versus cobalt bondedWC grades bonded by cobalt and nickel are benchmarked under dry sliding wear (T= 22/400°C; v= 0,1-10 m/s), abrasive wear (G65) and under dry turning and dry milling against different work piece alloys (C45E, 42CrMo4, 300WA, GG35, AlSi9Cu4Mg). The different elements explaining the wear resistance of NbC over WC will be illuminated. T2 - 73rd STLE Annual Meeting and Exhibition CY - Minneapolis, Minnesota, USA DA - 20.05.2018 KW - NbC KW - Cutting tool KW - Machining PY - 2018 AN - OPUS4-45852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tribology in hot steam for energy recovery N2 - The steam technology has attracted attention for recovering energy from waste heat in transportation systems. 40% of the calorific value of the fuel is wasted through the tailpipe. The use of waste heat recovery systems (WHRS) in cars and especially in trucks corresponds to possible energy savings in terms of less fuel consumption in the range of 7 – 18 %. This relates not only to the savings of fuel but also to the non-production of green house gas CO2. Steam expander form tribosystems, which can´t be lubricated with oils, as hot steam hydro-cracks these fluids. Suited tribomaterials as well as their tribo-oxidatively reaction layers must be first steam degradation resistant and for the tribotesting of such candidate material, tribological testing devices for a hot steam environment are needed. Not much is known so far about the tribological properties of any material system running under pressurized hot steam conditions. For these reasons and for being able to evaluate tribological properties in hot steam, BAM has developed and built a new and sealed tribometer for hot steam allowing evaluating tribological properties up to 700°C and 10 bars in gaseous atmospheres like hot steam or ethanol. Experimental results on the wear of self-mated aluminum oxide and MgO-ZrO2 couples show that friction as well as wear is largely determined by the above mentioned hydro-thermal conditions. In this system the presence of water and its amount available in the system either in liquid or in gaseous form plays a key role for wear behavior and can beneficial. Ethanol and/or water-ethanol mixtures can form beneficial tribofilms, also on specific diamond-like carbon films. T2 - 73rd STLE Annual Meeting and Exhibition CY - Minneapolis, Minnesota, USA DA - 20.05.2018 KW - Tribology KW - Hot steam KW - Tribometer PY - 2018 AN - OPUS4-45853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Niobium carbide NbC as cutting tool material and for wear protection N2 - The present paper illuminates the metallurgical progress on niobium carbide based hard metal developments, which are characterized by: a.) the substitution of cobalt binder by nickel, b.) the change from SPS to conventional sintering and c.) by switching from lab to pilot scale. The toughness was increased in the frame of these develop¬ments without loosening the hardness level. Stoichiometric and sub-stoichiometric, submicron NbC powders were used. The hardness-toughness profile of NbC grades match those of WC and cermet grades. Apart from the aforementioned parameters, the properties depend from the powder processing and sintering conditions. The functional profile of NbC and WC grades bonded by cobalt and nickel are benchmarked by 4-point bending strength, elastic moduli and hot hardness until 1000°C, dry sliding wear (T= 22/400°C; v= 0,1-10 m/s), abrasive wear (G65) and cutting performances under emulsion and coolant-free turning and milling against different alloys (C60, 100Cr6, 42CrMo4, X90CrMoV18, 300WA, GG35). T2 - 42nd International Conference and Exposition on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 21.01.2018 KW - NbC KW - Cutting tools KW - Wear PY - 2018 AN - OPUS4-45854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Machining with niobium carbide based tools N2 - The presentation deals about Niobium Carbide, its location, mine, products, uses, consumtion, and its tribological properties like micro-hardness, density and elastic-modulus. T2 - 59. Tribologie-Fachtagung 2018 CY - Göttingen, Germany DA - 24.09.2018 KW - Niobium carbide KW - NbC KW - Machining KW - Hardness PY - 2018 AN - OPUS4-46168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Machining with niobium carbide based tools N2 - The present work deals with Niobcarbid (NbC). Strategic reflections on tungsten carbide and more and more stringent toxicological restrictions for cobalt associated for both with spiraling stock market prices have attracted recently some attention for Niobium carbide as a substitute for tungsten carbide in machining. T2 - 59. Tribologie-Fachtagung CY - Goettingen, Germany DA - 24.09.2018 KW - Hard tungsten KW - Semi-finishing KW - Niobium carbide KW - Friction KW - Wear KW - NbC KW - Hard metal KW - Cobalt KW - Nickel KW - Fe3Al PY - 2018 SN - 978-3-9817451-3-9 SP - 48/1 EP - 48/11 AN - OPUS4-46170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Tailoring the functional profile of niobium carbide (NbC) as cutting tool materials and for wear protection N2 - The present work deals with Niobcarbid (NbC). Strategic reflections on tungsten carbide and more and more stringent toxicological restrictions for cobalt associated for both with spiraling stock market prices have attracted recently some attention for Niobium carbide as a substitute for tungsten carbide in machining. T2 - WORLDPM2018 CY - Beijing, China DA - 16.09.2018 KW - Niobium carbide KW - NbC KW - Machining KW - Hard turning KW - Cobalt KW - Nickel PY - 2018 AN - OPUS4-46198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huang, S. A1 - Vleugels, J. A1 - Cannizza, E. A1 - Woydt, Mathias A1 - Liu, Z. A1 - Mohrbacher, H. T1 - Niobium carbide based cermets with secondary carbide and carbonitride addition N2 - In this study, the influence of Ni binder content and carbide/carbonitride additions on the microstructure and mechanical properties of NbC-Ni matrix cermets were investigated. T2 - WORLDPM2018 CY - Beijing, China DA - 16.09.2018 KW - Cermet KW - Niobium carbide KW - Carbonitride KW - Sintering KW - Mechanical properties PY - 2018 SP - Part 5, 801 EP - 809 AN - OPUS4-46201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Uhlmann, E. A1 - Meier, P. A1 - Hinzmann, D. A1 - Kropidlowski, K. A1 - Prasol, L. A1 - Woydt, Mathias T1 - Dry turning with niobium carbide based tools N2 - In the present work it was shown that Niobium carbide (NbC) offers a competitive profile compared to tungsten carbide (WC) as cutting material regarding ist wear resistance preferably in metal cutting processes. T2 - WORLDPM 2018 CY - Beijing, China DA - 16.09.2018 KW - Turning KW - Semi-finishing KW - Niobium carbide KW - Tungsten carbide KW - Iron-based alloys KW - Aluminum PY - 2018 SP - Part 5, 775 EP - 784 AN - OPUS4-46203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Huang, S. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Cannizza, E. T1 - Tailoring the functional profile of niobium carbide (NbC) as cutting tool materials and for wear protection N2 - In the present work it was shown that the properties of NbCx, like micro-hardness, hot-hardness, sliding wear resistance, elastic modulus and toughness can be tailored by the C/Nb ratio, the addition of secondary carbides and the type of binder. T2 - WORLDPM2018 CY - Beijing, China DA - 16.09.2018 KW - Niobium carbide KW - Properties KW - Wear KW - Machining PY - 2018 SP - Part 5, 785 EP - 795 AN - OPUS4-46204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vleugels, J. A1 - Cannizza, E. A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - Influence of sintering temperature and carbide additions on the microstructure and mechanical properties of NbC-Ni based cermets N2 - This study reports on the effect of the sintering temperature and VC, Mo2C and TiC as well as the combination of Mo+VC on the densification, NbC grain growth, microstructure evolution as well as mechanical properties of novel NbC-Ni based cermets. KW - Cermet KW - Niobium carbide KW - Nickel KW - Sintering KW - Mechanical properties PY - 2018 DO - https://doi.org/10.3969/j.issn.1003-7292.2018.02.001 SN - 1003-7292 VL - 35 IS - 2 SP - 69 EP - 78 PB - Yingzhi Hejin Bianjibu CY - Zhuzhou AN - OPUS4-46136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Uhlmann, E. A1 - Hinzmann, D. A1 - Kropidlowski, K. A1 - Meier, P. A1 - Prasol, L. A1 - Woydt, Mathias T1 - Increased tool performance with niobium carbide based cutting materials in dry cylindrical turning N2 - In the present work it was shown that in contrast to WC tools NbC cutting tools show constant material removal VW at increased cutting speed vc combined with a higher process reliability. KW - Niobium carbide (NbC) KW - Tungsten carbide (WC) KW - Tool wear KW - Cylindrical turning PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465968 DO - https://doi.org/10.1016/j.procir.2018.08.238 SN - 2212-8271 VL - 77 SP - 541 EP - 544 PB - Elsevier AN - OPUS4-46596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Scholz, Christian A1 - Manier, Charles-Alix A1 - Brückner, A. A1 - Weihnacht, V. T1 - Slip-rolling resistance of ta-C and a-C coatings up to 3,000 MPa of maximum Hertzian contact pressure N2 - The slip-rolling resistances of hard and stiff thin films under high Hertzian contact pressures can be improved by optimizing the 'coating/substrate systems'. It is known from former investigations that the so-called 'egg-shell' effect is no general hindrance for high slip-rolling resistance of thin hard coatings. The coating stability depends more on specific deposition process and coating/substrate interface design. In this article it is experimentally shown, that pure amorphous carbon thin films with hardness between 15 and 63 GPa can be slip-rolling resistant several million load cycles under a maximum Hertzian contact pressures of up to 3.0 GPa. Whereas all coatings were stable up to 10 million load cycles in paraffin oil at room temperature, reduced coating lifetime was found in SAE 0W-30 engine oil at 120°C. It was shown how the coating hardness and the initial coating surface roughness influence the running-in process and coating lifetime. No clear correlation between coating hardness and coating lifetime could be observed, but friction coefficients seem to be reduced with higher coating hardness. Very low friction down to ~0.03 in unmodified engine oils was found for the hardest ta-C film.------------------------------------------------------------------------------------------------------------------------------------------------ Die Wälzbeständigkeit von harten und steifen Dünnschichten unter hohen Hertzschen Kontaktpressungen kann durch die Optimierung des 'Beschichtung/Substrat Systems' deutlich verbessert werden. Aus vorangegangenen Untersuchungen ist bekannt, dass der so genannte 'Eierschaleneffekt' kein generelles Hindernis für eine hohe Wälzbeständigkeit für harte Dünnschichten darstellen muss. Die Stabilität der Beschichtungen hängt vielmehr von dem spezifischen Prozessparametern und dem Schicht/Substrat Grenzflächendesign ab. In diesem Artikel wird experimentell nachgewiesen, dass reine amorphe Kohlenstoffdünnschichten mit Härtewerten zwischen 15 und 63 GPa für mehrere Millionen Lastzyklen unter maximalen Hertzschen Kontaktpressungen bis 3.0 GPa überrollbeständig sein können. Während alle Beschichtungen bis 10 Millionen Lastzyklen in Paraffinöl bei Raumtemperatur keine Defekte aufweisen wurde unter Verwendung eines SAE 0W-30 Motorenöls bei 120°C eine Verringerung der Überrollbeständigkeit nachgewiesen. Es wurde nachgewiesen, wie die Schichthärte und ursprüngliche Oberflächenrauheit der Beschichtung den Einlaufprozess und die Lebensdauer beeinflussen. Es konnte keine offensichtliche Korrelation zwischen Schichthärte und Lebensdauer festgestellt werden, allerdings wurde eine scheinbare Reduktion des Reibwertes mit steigender Schichthärte beobachtet werden. Dabei zeigte die härteste ta-C Schicht unter Verwendung des Motorenöls sehr geringe Reibwerte mit ~0.03. KW - ta-C KW - a-C KW - Friction KW - Wear KW - Slip-rolling KW - Rolling contact fatigue KW - Reibung KW - Verschleiß KW - Wälzen KW - Rollkontaktermüdung PY - 2012 DO - https://doi.org/10.1002/mawe.201200956 SN - 0933-5137 SN - 1521-4052 VL - 43 IS - 12 SP - 1019 EP - 1028 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias T1 - Application des données tribologiques des matériaux N2 - Un système tribologique (tribosystème) peut être conçu en vue d´assurer une résistance contre l´usure, d’assurer des transitions d´usure douce vers une usure sévère et de paramètres opérationnels susceptible engendrer l´usure adhésive à base d´une analyse des conditions d´opérations du tribosystème. Le taux d´usure kv représente une donnée tribologique principale de prescription relative à la résistance d´usure d´un matériau candidat. La valeur P×V[MPa×m/s] décrit une limite entre l´usure douce et sévère, elle s’apparente ainsi à la limite d’utilisation des matériaux au dessus duquel le matériau connaît un changement de mécanisme d’usure qui peut aller jusqu’au grippage. Cet article établit étape par étape ces caractéristiques à l’aide de plusieurs exemples et classe les plages des taux d´usures et valeurs P×V de matériaux. L´article éclaire aussi sur l´impact de paramètres opérationnels (rugosité, humidité relative, etc.) sur le frottement et le taux d´usure. PY - 2012 SN - 2114-2300 VL - 6 IS - BM 7 006v2 SP - 1 EP - 14 CY - Paris, France AN - OPUS4-26341 LA - fra AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Kelling, Norbert A1 - Hannemann, F. A1 - Berberich, N. A1 - Ziegele, H. T1 - Stribeck-type curves of alternative engine oils - Part II: AlSi17Cu4 liners N2 - This paper proposes a new test methodology to determine the potential of friction reduction by measuring for the tribosystem piston ring/ cylinder liner outside of the engine Stribeck-type curves involving test pieces prepared from engine components. The frictional work determined in the whole speed ränge of Stribeck-type curves are related to the wettability. The Variation of the friction coefficient with sliding speeddepends on the Chemical structure and Constitution of the base oil, the viscosityIndex, the metallurgy and surface topography of the liner and ring, and the friction modifiers used. Novel organic friction modifiers of low molecular mass not only reduce the friction coefficients under mixed / boundary lubrication, but also in the fluid film (hydrodynamic) regime. In addition, the influence of surface roughness on the wettability of surfaces can be significant for both static and dynamic wetting. For this reason, the interaction of the chemically different lubricants with the surfaces was also investigated to enable a correlation between the surface properties of the liquid and solid phases and the frictional behavior. T2 - 53. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß CY - Göttingen, Germany DA - 24.09.2012 PY - 2012 SN - 978-3-00-039201-6 VL - II SP - 63/1 EP - 63/14 CY - Aachen AN - OPUS4-26642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Kelling, Norbert A1 - Hannemann, F. A1 - Berberich, N. A1 - Ziegele, H. T1 - Stribeck-type curves of alternative engine oils: Part I: Gray cast iron liners N2 - Wear tests are often used in engine development in order to characterize the functional profile of surfaces interacting with lubricants. This paper proposes a new test procedure to determine Stribeck-type curves for the tribosystem piston ring/cylinder liner involving test pieces prepared from engine components. The variation of the friction coefficient with sliding speed depends on the structure and constitution of the base oil, the viscosity index, the surface topography of the liner and ring, and the friction modifiers used. Novel organic friction modifiers of low molecular mass not only reduce the friction coefficients under mixed / boundary lubrication, but also in the fluid film regime. In addition, the influence of surface roughness on the wettability of surfaces can be significant for both static and dynamic wetting. For this reason, the interaction of the lubricant with the surfaces was also investigated to enable a correlation between the surface properties of the liquid and solid phases and the tribological behavior. KW - Tribology KW - Wear tests KW - Automotive KW - Materials KW - Lubrication KW - Piston ring/cylinder KW - Surface topography KW - Wetting KW - Mixed/boundary lubrication PY - 2014 DO - https://doi.org/10.1520/MPC20120002 SN - 2165-3992 VL - 3 IS - 1 SP - 204 EP - 215 PB - ASTM International CY - West Conshohocken, Pa. AN - OPUS4-31206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Woydt, Mathias ED - Tung, S.C. ED - Totten, G.E. T1 - Nonpetroleum-based, no/low-sulphur, ash, and phosphorus, and bio-no-toxicity engine oil development and testing N2 - More and more, engine oils must minimize or avoid their effect on the durability of particulate filters and catalysts, and in the future, on terrestrial and aquatic environments. They must also maximize their contribution to fuel economy. Replacing hydrocarbon-based oils with environmentally friendly products is one of the ways to reduce the adverse effects on the ecosystem caused by the use of lubricants. By analyzing recent technological evolutions and future trends in engine oil specifications, with the associated consequences for the functional properties performed by base oils and individual additives, the need and potential application of alternative base oils with intrinsic properties will be displayed. The focus of this chapter is on alternative base oils. PY - 2012 SN - 978-0-8031-7036-0 IS - Chapter 18 SP - 317 EP - 329 CY - West Conshohocken, PA, USA AN - OPUS4-27605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kislov, S. A1 - Kislov, V. A1 - Ostrovsky, P. A1 - Woydt, Mathias T1 - Localized hardening and structuring of steel by a simple process N2 - Hardness is known as a property to fight agalnst adhesive wear and abrasion. Structuring is a modern path to enhanced hydrodynamic lubrication and Support deficient lubrication. The present paper illuminates a novel, simple and robust process to harden ferritic, perlitic or austenitic steels and/or to Implement a texturing to the contact zone, both as localized and “cold” treatments. These process steps guarantee dimensional stability. An integral Processing Step is the incorporation of substances and minerals into the surfaces, which substantially reduces friction and further increases wear resistance. This process transforms the structure of the subsurface Region from a pre-existing metallurgical structure into a new structure, preferably a martensitic one. These transformations of the pre-existing steels were confirmed by means of TEM and nano-indentation. For example, the plastic hardness of an X12Cr13 is increased from 2,530 MPa to 6,300 MPa. The resulting tribological effects will be shown for sliding and slip-rolling tribosystems. T2 - 53. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß CY - Göttingen, Germany DA - 24.09.2012 PY - 2012 SN - 978-3-00-039201-6 VL - II SP - 49/1 EP - 49/8 CY - Aachen AN - OPUS4-26641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Woydt, Mathias A1 - Scholz, Christian ED - Beswick, J.M. T1 - Slip-rolling resistance of alternative steels under high contact pressures in engine oils N2 - The inevitable increase of torque or load, because of lightweight approaches, pushes the oil-film temperatures on the teeth flanks of gears above 200°C, and requires alloys with higher strength and toughness properties. Furthermore, the real temperature on surfaces during the physical vapor deposition (PVD) or chemical vapor deposition (CVD) of thin films can exceed the annealing temperature of the state-of-the-art bearing and gear materials, such as AISI 52100 (1.3505), 16MnCr5 (1.7131), 21NiCrMo (1.6523), and 30CrMoV9 (1.7707). Such trends call for slip-rolling-resistant, alternative alloys suited for contact stresses above P0max of >2.2 GPa. The tribological profile under slip-rolling conditions at 120°C in a factory engine oil (SAE 0W-30, ACEA A3/B4, ν120°C = 5.33 mPa, HTHS150°C = 3.0 mPa) until 10 × 106 load cycles between P0max of 2.25 GPa to 3.92 GPa of uncoated 100Cr6 (1.3505, “PBQ”), 102Cr6 (1.2067), Cronidur 30 (1.4108, DESU), 45SiCrMo6 (1.8062, CVEM), 40SiNiCrMo1 [vacuum arc remelting (VAR)], CSS-42L (AMS 5932, vacuum induction melting (VIM)-VAR, and carburized), 36NiCrMoV1-5-7 (CAB), ASP2012 (ASP), and 20MnCr5 (1.7131, carburized) was established in twin disk machines (Amsler-type and 2Disk). The present benchmark illuminates the tribological impact of uncoated bearing steels in comparison to uncoated alternative steel alloys on friction, wear and slip-rolling resistance, as well as load carrying capacity. Iron-based steel alloyed with silicon or molybdenum reduces alloying costs and avoids thermo-chemical treatments. This benchmark suggests considering an extension to fracture toughness from hardness and strength as a relevant property for slip-rolling alloys. If slip-rolling resistant, the wear rates of the metallurgical different steels were more or less within one order of magnitude, but the influence of increasing contact stresses on the tribological profile differed significantly. KW - Slip rolling KW - Bearing steel KW - High toughness steel KW - Silicon KW - Molybdenum KW - Rolling KW - contact fatigue KW - High contact pressure KW - Low friction PY - 2015 SN - 978-0-8031-7605-8 DO - https://doi.org/10.1520/STP158020140018 SN - 2160-2050 N1 - Serientitel: ASTM International - Selected Technical Papers (STP) – Series title: ASTM International - Selected Technical Papers (STP) VL - 1580 SP - 210 EP - 238 AN - OPUS4-33121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - The functional profile of hard metals and MMCs based on niobium carbide T2 - Int. Symposium on Wear Resistant Alloys for the Mining and Processing Industry CY - Campinas, Sao Paulo, Brazil DA - 2015-05-04 PY - 2015 AN - OPUS4-33178 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Kelling, Norbert T1 - Stribeck-type curves of alternative engine oils - Part I: Gray cast iron liners N2 - Wear tests are often used in engine development in order to characterize the functional profile of surfaces interacting with lubricants. This paper proposes a new test procedure to determine Stribeck-type curves for the tribosystem piston ring/cylinder liner involving test pieces prepared from engine components. The Variation of the friction coefficient with sliding speed depends on the structure and Constitution of the base oil, the viscosity index, the surface topography of the liner and ring, and the friction modifiers used. Novel organic friction modifiers of low molecular mass not only reduce the friction coefficients under mixed / boundary lubrication, but also in the fluid film regime. In addition, the influence of surface roughness on the wettability of surfaces can be significant for both static and dynamic wetting. For this reason, the interaction of the lubricant with the surfaces was also investigated to enable a correlation between the surface properties of the liquid and solid phases and the tribological behavior. T2 - 52. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Deutschland DA - 26.09.2011 PY - 2011 SN - 978-3-00-035439-7 VL - Part I SP - 32/1 EP - 32/12 AN - OPUS4-31752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Niobium carbide (NBC) as wear resistant hardmetal in opened and closed tribosystems T2 - 2. Int. Brazilian Conf. on Tribology - TriboBR 2014 CY - Foz do Iguacu/Paraná, Brazil DA - 2014-11-03 PY - 2014 AN - OPUS4-31753 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Manier, Charles-Alix A1 - Brückner, A. A1 - Weihnacht, V. T1 - Slip-rolling resistant thin film ta-C coatings for up to 3.000 MPa of Hertzian contact pressure T2 - 50. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendung CY - Göttingen, Germany DA - 2009-09-21 KW - Slip-rolling KW - ta-C coating KW - a-C coating KW - Wear KW - Hertzian pressure PY - 2009 SN - 978-3-00-028824-1 VL - II SP - 55/1 EP - 55/11 CY - Aachen AN - OPUS4-31754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Habig, Karl-Heinz A1 - Woydt, Mathias ED - Grote, K.-H. ED - Feldhusen, J. T1 - Tribologie N2 - Tribologie ist die Wissenschaft und Technik von aufeinander einwirkenden Oberflächen in Relativbewcgung (DIN 50 323, Teil I). Diese Definition ist aus der englischen Originalfassung abgeleitet: Tribology - Science and tcchnology of interacting surfaces in relative motion and the practiccs related thereto 11 ]. Die Tribologie umfasst die Teilgebiete Reibung, Verschleiß und Schmierung. Sie steht in enger Beziehung zu den Werkstoffen der beteiligten Körper, deshalb ihre Behandlung in Teil H. PY - 2014 UR - http://link.springer.com/chapter/10.1007/978-3-642-38891-0_38 SN - 978-3-642-38890-3 SN - 978-3-642-38891-0 DO - https://doi.org/10.1007/978-3-642-38891-0 SP - Kap. E 5, E89-E97, 297-305 PB - Springer-Vieweg CY - Berlin Heidelberg AN - OPUS4-31757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Azouigui, S. A1 - Silvestri, Z. A1 - Zerrouki, C. A1 - Bouhtiyya, S. A1 - Plimmer, M.D. A1 - Spaltmann, Dirk A1 - Kovalev, Alexander A1 - Woydt, Mathias A1 - Pinot, P. T1 - Angle resolved scattering as a tribological investigation tool for surface characterization N2 - This paper shows how Angle-Resolved Scattering can reveal wear on engineered surfaces. The samples studied, three discs made of steel 100Cr6H used in gear wheels in the automotive industry, were assessed after they had undergone ball-on-disc tests. Scattering maps recorded for spatial frequencies from 0.1 µm-1 to 2.7 µm-1 show a contrast inversion around 0.36 µm-1 revealing the wear trace. Besides measurements of rms roughness, where mean values are 20 nm and 24 nm depending on the locations considered, stationarity and isotropy, we demonstrate the ability of the technique to reveal localized wear on this type of surface in a rapid, robust and convenient way. We show that the tool trace is influenced by the load magnitude rather than by the number of oscillation cycles and highlight the key role played by surface roughness in how the sample responds to wear tests. KW - Surface roughness KW - Angle-resolved scattering KW - Wear KW - Isotropy PY - 2015 DO - https://doi.org/10.1016/j.wear.2014.12.040 SN - 0043-1648 VL - 326-327 SP - 58 EP - 67 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-33021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Niobium and its compounds for a reliable value chain - more with less T2 - First International Conference on Minerals in the Circular Economy CY - Espoo, Finland DA - 2014-11-26 PY - 2014 AN - OPUS4-32082 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Hardmetals in tungsten carbide substituted by niobium carbides - Influence of stoichiometry and process on tribological behavior T2 - 70. STLE Annual Meeting CY - Dallas, Texas, USA DA - 2015-05-17 PY - 2015 AN - OPUS4-33261 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Influence of stoichiometry and process on the tribological profile of hardmetals based on niobium carbide (NbC) T2 - POWDERMET 2015. Int. Conf. on Powder Metallurgy & Particulate Materials CY - San Diego, USA DA - 2015-05-17 PY - 2015 AN - OPUS4-33210 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, S.G. A1 - Vanmeensel, K. A1 - Mohrbacher, H. A1 - Woydt, Mathias A1 - Vleugels, J. T1 - Microstructure and mechanical porperties of NbC-matrix hardmetals with secondary carbide addition and different metal binders N2 - NbC has a relatively high hardness (19.6 GPa) and melting temperature (3600 °C) and is usually applied as a grain growth inhibitor in WC–Co hardmetals. The current study reports on the influence of the sintering technology and overall chemical composition on the microstructure and mechanical properties of NbC-based hardmetals, using Co as a binder. The partial replacement of NbC by 5 wt.% WC, Mo2C, VC or TiC allows one to significantly improve the hardness and toughness of the NbC–Co materials. The influence of different binders, i.e., Co, 316L stainless steel and Fe3Al on the microstructure and mechanical properties of NbC-based hardmetals was also investigated. The powder mixtures were sintered in the solid state by PECS and liquid state by conventional vacuum sintering. Detailed microstructural analysis was conducted by EPMA elemental mapping and WDS point analysis. Mechanical properties, including Vickers hardness and indentation toughness were assessed. KW - Niobium carbide KW - Sintering KW - Grain growth KW - Microstructure KW - Mechanical properties PY - 2015 DO - https://doi.org/10.1016/j.ijrmhm.2014.10.014 SN - 0263-4368 SN - 0958-0611 VL - 48 SP - 418 EP - 426 PB - Elsevier AN - OPUS4-31974 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholz, Christian A1 - Woydt, Mathias A1 - Mohrbacher, H. ED - Mohrbacher, H. T1 - Slip-rolling resistance and load carrying capacity of 36NiCrMoV1-5-7 steel N2 - The approaching CO2 targets have now enforced automotive OEMs to engage R&D efforts also in powertrain to reduce friction, increase lifetime properties, and load carrying capacities of running systems. Martensitic steels such as 36NiCrMoV1-5-7 have a great potential to be used in automotive powertrain applications due to its favorable mechanical properties. In order to realize lightweight strategies, it is essential that steels with improved fracture toughness values and higher annealing temperatures with regard to higher contact pressures and possible thin film coating application be considered. State-of-the-art steels, like 16MnCr5, 21NiCrMo, 30CrMoV9, and 100Cr6 are not able to sustain a further increase in torque or load during operating time as well as annealing effects under higher oil or deposition temperatures. Therefore, the recent research on the slip-rolling resistance, frictional, and wear behavior of steels such as 36NiCrMoV1-5-7, Cronidur 30 (AMS 5898), 20MnCr5 (SAE 4820 or 5120), and 100Cr6H (SAE E52100) showed that possible lean alloying concept alternatives with promising performance characteristics are already available. T2 - 2nd International symposium on fundamentals and applications of Mo and Nb alloying in high performance steels CY - Jeju Island, South Korea DA - 24.04.2013 KW - Molybdenum KW - Steel KW - Slip-rolling resistance KW - High contact pressure KW - Oil PY - 2015 SN - 978-0-692-34620-4 DO - https://doi.org/10.1520/MPC20130022 SN - 2165-3992 VL - 2 SP - 191 EP - 203 AN - OPUS4-32668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Criqui, B. A1 - Linneman, T. A1 - Desplanches, G. A1 - Woydt, Mathias ED - Bartz, Wilfried J. T1 - Tribological performances of new triboactive (Ti,Mo)(C,N) and Tin-2Cr2O2n-1 as piston ring and cylinder liner coatings interacting with bio-no-tox lubricants T2 - 15th International colloquium tribology - Automotive and Industrial Lubrication CY - Ostfildern, Germany DA - 2006-01-17 KW - Thermisches Spritzen KW - Triboactif KW - Beschichtungen KW - APS KW - HVOF KW - (Ti,Mo)(C,N) KW - Tin-2Cr2O2n-1 KW - Bio-no-tox-Öle KW - PAG KW - Ester PY - 2006 SN - 3-924813-62-0 SP - Paper 15_P4_Woydt_Plenar, 1 EP - 10 CY - Ostfildern AN - OPUS4-31742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Berger, L.-M. A1 - Saaro, S. A1 - Woydt, Mathias T1 - WC-(W,Cr)2C-Ni - die unbekannte Hartmetallschicht / WC-(W,Cr)2C-Ni - the unknown hardmetal coating N2 - Die Zusammensetzung WC-(W,Cr)2C-7%Ni gehört zu den kommerziell verfügbaren Standardzusammensetzungen für Hartmetallspritzpulver und -schichten. Abweichend davon wird sie mit unterschiedlichen Bezeichnungen wie WC-'CrC'-Ni, WC-Cr3C2-Ni oder WC-NiCr gehandelt. In diesem Beitrag werden die spezifischen Mikrostrukturen und Phasenzusammensetzungen der Beschichtungspulver und der HVOF-gespritzten Schichten vorgestellt. Das besondere Anliegen ist es, dass noch unbekannte Potenzial dieser Zusammensetzung, ihre außerordentliche Oxidationsstabilität und das günstige Verhalten im ungeschmierten Reib-/Gleitverschleiß aufzuzeigen. Diese Eigenschaften werden mit denen von WC-10%Co-4%Cr-Schichten verglichen. Da seit dem Zeitpunkt der Entwicklung der Zusammensetzung 50 Jahre verstrichen sind, kann davon ausgegangen werden, dass sie bei weitem nicht optimal auf die uns heute zur Verfügung stehende Anlagentechnik abgestimmt ist. Somit ist der Impuls für weitere Verbesserungen und neue Anwendungen gegeben. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The composition WC-(W,Cr)2C-7%Ni is a standard commercially available composition for hardmetal feedstock powders and coatings, but it is sold under a variety of designations including WC-'CrC'-Ni, WC-Cr3C2-Ni and WC-NiCr. In this paper the specific microstructures and phase compositions of the feedstock powder and the HVOF-sprayed coatings are presented with a view to shedding light on the still-unknown application potential of this composition as well as its extraordinary oxidation resistance and advantageous behaviour in dry sliding conditions. These properties are compared with those of WC-10%Co-4%Cr coatings. As 50 years have passed since it was developed, this composition can well be said to be far from optimal for today’s HVOF equipment. There is hence room for improvement as well as for new applications. KW - Thermal spraying KW - Dry sliding KW - High temperature KW - APS KW - HVOF KW - WC KW - Ni KW - (W,Cr)2C KW - Dry friction PY - 2008 SN - 1866-6248 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 1 IS - 1 SP - 37 EP - 40 PB - DVS-Verl. CY - Düsseldorf AN - OPUS4-31745 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias T1 - Oil free machinery and ZERO WEAR - Dream or reality? N2 - Original equipment manufacturers (OEMs) and end-users perceive 'Zero Wear' differently. The 'Zero Wear' approach will be put into a general relation for different applications and illuminated by individual paths, either based on monolithic materials, thin film coatings or alternative base oils, featuring triboactive materials and lubricious oxides for tribological engine components and dry running foil bearings or specific DLC, ta-C and novel Zirconium-based thin film coatings for concentrated contacts above FZG 14 and alternative engine oils (NoSAP & bio-no-tox). The associated tribometric test equipments for these examples will also be detailed. KW - Zero wear KW - SRV KW - Triboactive coatings KW - (Ti,Mo)(C,N) KW - Tin-2Cr2O2n-1 KW - Magnéli KW - DLC KW - Zr(C,N), KW - ta-C KW - Polyglycol PY - 2011 DO - https://doi.org/10.2474/trol.6.101 SN - 1881-2198 VL - 6 IS - 1 SP - 101 EP - 112 CY - Tokyo, Japan AN - OPUS4-31746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Berger, L.-M. A1 - Stahr, C.C. A1 - Saaro, S. A1 - Thiele, S. A1 - Woydt, Mathias A1 - Kelling, Norbert T1 - High temperature tribology up to 7.5 m/s of thermally sprayed coatings of the TiO2-Cr2O3 system and (Ti,Mo)(C,N)-Ni(Co) T2 - 49. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Deutschland DA - 2008-09-22 KW - Thermal spraying KW - Dry sliding KW - High temperature KW - APS KW - HVOF KW - WC KW - Ni KW - Cermet KW - (Ti,Mo)(C,N) KW - Dry friction PY - 2008 SN - 978-3-00-025676-9 VL - I SP - 1/1 EP - 1/15 AN - OPUS4-31749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Hardmetals based on niobium carbide (NbC) versus casted MMCs based on NbC N2 - This paper indicates that the tribological behavior under dry sliding of a Fe3Al-niobium carbide (NbC) composite prepared by pyrometallurgical synthesis was compared to NbC-based hard metals bonded by cobalt or Fe3Al. The dry sliding wear resistance (0,1-7/10 m/s) of the present Fe3Al-NbC with ∼60% NbC was close to those known of NbC-based hard metals. No grain pull-outs or fragmentations of the NbC grains were seen in the wear tracks, as a metallurgical interphase was formed between matrix and NbC grains. T2 - 39. Int. Conf. Expos. on Advanced Ceramics and Composites CY - Daytona Beach, Florida, USA DA - 25.01.2015 KW - Metal matrix composites KW - Hard metals KW - Niobium carbide KW - Cobalt KW - Grains KW - Matrix PY - 2015 DO - https://doi.org/10.1002/9781119211310.ch10 AN - OPUS4-32556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Niobium carbide for a reliable value chain T2 - 39. Int. Conf. & Expos. on Advanced Ceramics and Composites CY - Daytona Beach, Florida, USA DA - 2015-01-25 PY - 2015 AN - OPUS4-32558 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burbank, John Theodore A1 - Woydt, Mathias T1 - Comparison of slip-rolling behaviour between 20MnCr5 gear steel, 36NiCrMoV1-5-7 hot working tool steel and 45SiCrMo6 spring steel N2 - The automotive industry places significant importance on downsizing components to achieve greater efficiency. The goal of reducing CO2 emissions has led to the development of lightweight materials that are also able to enhance performance. In light of these aspirations, the aim of this study is to characterize two novel, high-performance steels, as well as a 'classical' gear steel for comparison with each other and currently applied materials. The gear steel underwent carburization and subsequent deep freezing treatments in an attempt to yield discrete sample groups with respect to residual austenite. The high-performance steels were heat treated as recommended by their respective manufacturers, and were not carburized. Elemental analyses were conducted by multiple methods to ensure accurate results. Residual austenite contents of the steels and the depth profiles of residual stresses were determined by X-ray diffraction (XRD). Hardness profiles were taken from the testing surfaces into the material core. The carburization of 20MnCr5 led to higher hardness and the greater concentration of carbon in the carburization zone more representative of a hardened SAE E52100, or 100Cr6/102Cr6, than of a non-carburized 20MnCr5. Residual austenite contents ranging from approximately 6–14 vol% were generated, though effectively providing only two, rather than the desired four discrete sample groups. Residual stresses from machining and carburization were measured directly at the sample surface, and from carburization alone below the surface. The high-performance steels fulfilled manufacturer expectations in terms of elemental content, hardness between 50 and 55 HRC and strongly martensitic microstructure character. Finally, slip-rolling endurance testing (T=+120 °C, 10,000,000 cycles, approximately 19 days in a factory fill engine oil) was carried out on all materials, whereby coefficient of friction distributions during testing and wear coefficients after testing were calculated. Testing was performed up to and including P0Mean=1.94 GPa (P0Max=2.91 GPa, FN=2000 N). Ultimately, the non-carburized high-performance steels showed competitive wear performance and better friction behaviour than the carburized 20MnCr5, which has been attributed to their work hardening capability. KW - Gear KW - Bearing KW - Slip-rolling KW - Friction KW - Residual austenite KW - Wear resistance PY - 2015 DO - https://doi.org/10.1016/j.wear.2015.01.024 SN - 0043-1648 VL - 328-329 SP - 28 EP - 38 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32578 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. ED - Gyekenyesi, A. ED - Halbig, M. T1 - Tribological background for the use of niobium carbide (NBC) as cutting tools and for wear resistant tribosystems N2 - The tribological profile of rotating disks made of binder-less niobium carbide (hot-pressed NbC) and cobalt-bonded NbC (NbC-8Co) mated against alumina (99.7%) were determined under unidirectional sliding tests (0.1 m/s to 8.0 m/s; 22°C and 400°C) as well as in oscillation tests (f= 20 Hz, Δx= 0.2 mm, 2/50/98% rel. humidity, n= 105/106 cycles) under un-lubricated (dry) conditions. In addition, the microstructure and mechanical properties of NbC and NbC bonded with 8% cobalt were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where the NbC-8Co presented above 7 m/s the lowest wear rates so far in such a bench mark. NbC and NbC-8Co exhibited low wear rates under dry sliding associated with P·V high load carrying capacity. The tribological profile established revealed a strong position of NbC bearing materials under tribological considerations and for closed tribo-systems against traditional references. T2 - 38th International conference on advanced ceramics and composites CY - Daytona Beach, FL, USA DA - 26.01.2014 KW - Sliding friction KW - Wear KW - Ceramic KW - Oscillation KW - Coating KW - NbC KW - Niobium carbide KW - Cobalt KW - Hard metal PY - 2014 SP - Paper 1 EP - Paper 21 AN - OPUS4-32561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Kelling, Norbert A1 - Hartelt, Manfred A1 - Igartua, A. A1 - Areitioaurtena, O. A1 - Seyfert, C. A1 - Luther, R. ED - Bartz, Wilfried J. T1 - Tribological performance of bio-no-tox engine oils and new triboactive materials for piston ring/cylinder liner systems T2 - 15th International colloquium tribology - Automotive and Industrial Lubrication CY - Ostfildern, Germany DA - 2006-01-17 PY - 2006 SN - 3-924813-62-0 SP - Paper 15_E7_Woydt_Bio-no-tox, 1-6 CY - Ostfildern AN - OPUS4-31761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Manier, Charles-Alix A1 - Ziegele, H. A1 - Barriga, J. A1 - Goikoetxea, J. T1 - Zirkonium-basierte Dünnschichten in hochbeanspruchten Wälzkontakten als Alternative zu DLC und ta-C T2 - 50. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendung CY - Göttingen, Germany DA - 2009-09-21 KW - Wälzbeständigkeit KW - Zirkon KW - Zr(C,N) KW - DLC KW - Überrollbeständigkeit KW - Nanostrukturierte Schichten PY - 2009 SN - 978-3-00-028824-1 VL - II SP - 58/1 EP - 58/14 CY - Aachen AN - OPUS4-31763 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Kelling, Norbert T1 - Zylinderlaufbahnen aus Aluminiumlegierungen und deren tribologische Weiterentwicklungen durch Schmierstoffe und Metallurgie T2 - 47. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 2006-09-25 KW - Kolbenring KW - Zylinderlaufbahn KW - AlSi KW - Aluminium KW - Triboaktive Werkstoffe PY - 2006 SN - 3-00-019670-6 VL - II SP - 71/1 EP - 71/11 CY - Aachen AN - OPUS4-31764 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - The context and nature of environmentally acceptable lubricants T2 - F+L Week 2015. Conference & Exhibition CY - Singapore DA - 2015-03-10 PY - 2015 AN - OPUS4-32869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - The use of niobium carbide (NbC) as cutting tools and for wear resistant tribosystems N2 - The tribological profile of alumina (99.7%) mated against rotating disks made in binder-less niobium carbide (NbC) and cobalt-bonded NbC were determined under unidirectional sliding tests (0.1 m/s to 8.0 m/s; 22 °C and 400 °C) as well as in oscillation tests (f = 20 Hz, Δx = 0.2 mm, 2/50/98% rel. humidity, n = 105/106 cycles) under unlubricated (dry) conditions. In addition, the microstructure and mechanical properties of binderless NbC and NbC bonded with 8% cobalt were determined as well. The reason for testing hot-pressed NbC was to avoid side effects generated by sintering additives and/or second phases. The tribological data obtained were benchmarked with different ceramics, cermets and thermally sprayed coatings. NbC and cobalt-bonded NbC exhibited low wear rates under dry sliding associated with high load carrying capacity. The tribological profile established revealed a strong position of NbC bearing materials under tribological considerations and for closed tribo-systems against traditional references, such as WC, Cr3C2 and (Ti,Mo)(C,N). KW - Sliding friction KW - Sliding wear KW - Ceramic KW - Oscillation KW - Coating KW - NbC KW - Niobium carbide KW - Hard metal KW - Cobalt PY - 2015 DO - https://doi.org/10.1016/j.ijrmhm.2014.07.002 SN - 0263-4368 SN - 0958-0611 VL - 49 SP - 212 EP - 218 PB - Elsevier AN - OPUS4-32896 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias T1 - Status on Polyglycol-based engine oils T2 - Euopean Base Oils & Lubricant Summit CY - Alicante, Spain DA - 2014-09-17 PY - 2014 AN - OPUS4-31494 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - Niobcarbid - Ein vergessener Hartstoff für den Verschleißschutz in offenen und geschlossenen Tribosystemen N2 - Das triboiogische Profil von binderlosem NbC und mit 8% bzw. mit 12% Cobalt oder 12% FeaAl gebundenem NbC wird unter unidirektionaler Gleitreibung (v= 0,1-10 m/s, T= 22°C und 400°C) und unter oszillierender Gleitreibung vergleichend gegenüber Ingenieurkeramiken und Hartmetallen dargestellt. Zusätzlich werden die 4-Punkt-Biegebruchfestigkeit, elastische Eigenschaften (E,G) bis 1.000°C die lastabhängige Mikrohärte sowie die Phasenzusammensetzung und Gefügestrukturen vorgestellt. Die Verschleißkoeffizienten des binderlosen NbC lagen bei T unterhalb von 10'6mm31 / *N* m, während diejenigen der cobaltgebundenen NbCs mit ansteigender Gleitgeschwindigkeit von 2-4 10‘6 mm3/Nm bei 0,1 m/s auf 5-7 10"7 mm3/Nm bei 10 m/s abnahmen. Die Verschleißkoeffizienten bei 400°C lagen für die NbCs generell unterhalb von 10‘6 mm3/Nm. Das triboiogische Lasttragevermögen im Trockenlauf, ausgedrückt als PV-Wert, nimmt mit ansteigender Gleitgeschwindigkeit auf 100 W/mm2 zu. Bedingt durch die geringe Löslichkeit von NbC in Legierungen offenbarten erste Zerspanversuche mit verschiedenen Stählen eine gegenüber WC-basierten Schneidstoffen signifikant angehobene Zerspanungsvolumina. Somit offenbart NbC in offenen und geschlossenen Tribosystemen Anwendungspotentiale. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 03/1 EP - 03/14 AN - OPUS4-31531 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -