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 U6 - 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 - GEN A1 - Girard, L. A1 - Tung, S. A1 - Woydt, Mathias A1 - Bachelder, D. ED - Totten, G. E. ED - Shah, J. S. ED - Forester, D. R. T1 - Automotive engine lubricants N2 - In 2003, ASTM Manual 37, Fuels and Lubricants Handbook: Technology, Properties, Performance and Testing, featured a chapter discussing automotive lubricants, including engine oils, automatic transmission fluids, manual transmission fluids, gear lubricants, and greases. This chapter, by Schwartz, Tung, and McMillan, surveyed all of these classes of lubricants, up to its publication in 2003. More recently, the period between 2003 and 2010 has been addressed as part of a book copublished by ASTM and SAE International (coeditors Simon Tung and George Totten), where Fox surveyed the development of engine oil specifications that emerged during those years. This chapter surveys the evolution of engine oil design and testing since 2002 and concludes with insights into future directions offered by recent tribological research. Our objective is to provide a reader new to the field with an understanding of the following: - Engine oil composition and formulation - North American engine oil specification development, and an outline of emergent European specifications - How emergent specifications and legislative requirements are linked to the introduction of new engine hardware - How tribological innovation can contribute to future enhancements in engine efficiency In parallel, we will provide several tables comparing groups of contemporaneous specifications. KW - Engine oil design KW - Engine oil testing PY - 2019 UR - https://www.astm.org/mnl3720160034.html SN - 978-0-8031-7089-6 SN - 978-0-8031-7090-2 U6 - https://doi.org/10.1520/mnl3720160034 SP - 753 EP - 863 PB - ASTM International CY - West Conshohocken, PA ET - 2 AN - OPUS4-53977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Huang, S. A1 - Cannizza, E. A1 - Vleugels, J. A1 - Mohrbacher, H. T1 - Niobium carbide for machining and wear protection - Evolution of properties N2 - The sales of niobium carbide (NbC) have grown in the last years, but NbC is still a hidden carbide and mainly used as grain growth inhibitor in hard metals. In the present work it was shown that the progress in the key properties, like HV30, KIC and strength, followed by machining and tribological results of the respective NbC grades. KW - Niobium carbide KW - Hard metals KW - Tribology PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-485507 SN - 0026-0657 VL - 74 IS - 2 SP - 82 EP - 89 PB - Elsevier Ltd. AN - OPUS4-48550 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias T1 - Sub-stoichiometric oxides for wear resistance N2 - In the present work it was shown that the tribologcal profiles of special model oxides under dry unidirectional sliding have shown, that sub-oxides have a contribution to the tribological behavior of carbides and cermets, when they are tribo-oxidatively formed, because their tribological profiles as monolithic materials are homologous in part or totally, or compete with hardmetals or cermets, depending from the operating conditions regarded. KW - Sub-oxide KW - Friction KW - Wear KW - Carbide KW - Hardmetal PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-498154 SN - 0043-1648 N1 - Eine identische Version zu diesem Artikel wurde publiziert unter: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066 - An identical version to this article was published under: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066 VL - 440-441 SP - 203104-1 EP - 203104-7 PB - Elsevier CY - Amsterdam AN - OPUS4-49815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Sato, K. A1 - Brandt, Guido A1 - Schmid, Thomas A1 - Sasaki, S. A1 - Woydt, Mathias T1 - Wear behaviour of MgO stabilized zirconia in hot steam environment up to 400°C N2 - Self-mated magnesia stabilized zirconia (Mg-PSZ) ceramic sliding couples have been investigated at 100 N load (P0max= 1324 MPa) in oscillating sliding conditions in different humidity conditions in air and in hot steam. Temperatures have been varied up to 400 °C and pressures up to 6 bars. The results show that the wear behavior of MgO-ZrO2 under high Hertzian contact pressures is strongly dependent on temperature and is similar for both dry oscillating and oscillating in hot steam. However, although the evolution in wear rates on temperature is similar and the wear rates of MgO-ZrO2 plunged above 300 °C in hot steam and air by nearly three orders of magnitude, SEM micrographs revealed in hot steam at 400 °C smooth wear tracks. In contrast, hot steam enhanced the tribochemistry of self-mated alumina couples and reduced wear rates. Hot steam decreased the coefficients of friction of MgO-ZrO2 with increasing temperature, but not the wear rates. KW - Hot steam KW - Zirconia KW - Friction KW - Wear KW - Tribofilm KW - Raman spectroscopy PY - 2019 U6 - https://doi.org/10.1016/j.wear.2019.01.047 VL - 426-427 SP - 428 EP - 432 PB - Elsevier B.V. AN - OPUS4-47873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pimentel, A. S. O. A1 - Guesser, W. L. A1 - Custódio da Silva, W. J. R. A1 - Portella, Pedro Dolabella A1 - Woydt, Mathias A1 - Burbank, J. T1 - Abrasive wear behavior of austempered ductile iron with niobium additions N2 - Carbidic Austempered Ductile Iron (CADI) microstructures containing eutectic carbides can be produced by the addition of carbide stabilizing elements, such as chromium. Carbides formed from the addition of Cr are eutectic of M3C type. The presence of such hard phases can enhance the abrasion wear resistance of ductile iron. A new CADI can be produced by the addition of Nb. Niobium carbide particles are formed in the beginning of solidification and remain stable once they are insoluble in solid iron matrix. The dry sand abrasive wear resistance of ductile irons alloyed with 1.0, 1.8, and 2.4 wt% Nb were tested in both “as-cast” and “heat treated” conditions using standard ASTM G65. Results were compared to abrasive wear data obtained on ductile iron alloyed with 1 wt% Cr, CADI (1 wt% Cr), and the basic composition of iron without carbide stabilizing elements. In the “ascast” condition, the addition of Nb did not lead to a reduction in wear, while CADI with Nb is a promising substitute for CADI with Cr addition, because both materials showed very similar values of abrasion resistance. Micro-ploughing and micro-cutting mechanisms were observed on the worn surfaces of ductile irons. Abrasive wear resistance of these alloys was correlated with the volume fraction of carbides. KW - arbidic austempered ductile iron KW - Ductile iron KW - Niobium alloying KW - Abrasion PY - 2019 U6 - https://doi.org/10.1016/j.wear.2019.203065 VL - 2019 IS - 440–441 SP - 203065 PB - Elsevier CY - Amsterdam, Niederlande AN - OPUS4-50784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pimentel, A. S. O. A1 - Guesser, W. L. A1 - Portella, Pedro Dolabella A1 - Woydt, Mathias A1 - Burbank, J. T1 - Slip-rolling behavior of ductile and austempered ductile iron containing niobium or chromium N2 - The use of high niobium alloyed cast iron alloys is a relatively new approach in which the niobium addition intends to improve the properties of the material by the precipitation of hard niobium carbides during solidification. Steels can be replaced by ductile cast iron in some rolling applications, such as gears and cams, in order to reduce material costs. The aim of this work is to evaluate ductile iron alloyed with 1 weight percent (wt.%) niobium for the as cast specimens and with 1.8 wt.% and 2.4 wt.% niobium for the austempered specimens under lubricated slip-rolling tests using mixed/boundary conditions in an Amsler-type machine. Austempered ductile iron (ADI) alloyed with 1 wt.% chromium, or Carbidic ADI, was tested for comparison. For the as cast conditions, the niobium addition resulted in an increase of wear resistance owing to the low contact pressure of these tests. However, for the austempered specimens, the best performance was found for unalloyed ADI. The main factor acting in the initiation and propagation of cracks in ductile iron is the presence of the graphite nodules. The coarse carbides also contributed to the initiation of cracks and spalling of the material. KW - Ductile iron KW - Niobium alloying KW - Slip-rolling KW - Carbidic austempered ductile iron PY - 2019 U6 - https://doi.org/10.1520/MPC20180188 SN - 2165-3992 SN - 2379-1365 VL - 8 IS - 1 SP - 402 EP - 418 PB - ASTM International CY - West Conshohocken, Pa. AN - OPUS4-51209 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 U6 - 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 -