TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - Friction and wear of binder-less niobium carbide N2 - The tribological profile of alumina (99.7%) mated against binder-less niobium carbide (NbC) rotating disks were determined unidirectional sliding tests (0.1–7.5 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 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 exhibited low wear rates under dry sliding associated with high load carrying capacity. The tribological profile established revealed a strong position of NbC under tribological considerations and for closed tribo-systems against traditional references, such as WC, Cr3C2, (Ti,Mo)(C,N), etc. KW - Sliding friction KW - Sliding wear KW - Ceramic KW - Coating KW - NbC PY - 2013 U6 - https://doi.org/10.1016/j.wear.2013.07.013 SN - 0043-1648 VL - 306 IS - 1-2 SP - 126 EP - 130 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-28985 LA - eng 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 U6 - 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 - 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 - 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-316129 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 - 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 U6 - 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 - 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 - 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-444608 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 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - Densification and tribological profile of niobium oxide N2 - The origin of the intrinsic wear resistance of NbC-based materials is investigated through an assessment of the tribological performance of fully dense, crack-free spark plasma sintered Nb2O5 (here as a reduced polymorph: monoclinic Nb12O29 or NbO2.416). The most likely wear mechanism on NbC is the tribo-oxidation to Nb2O5. The unlubricated (dry) friction and wear behavior of alumina (99.7%) mated against rotating disks of crack-free niobium(V)oxide (Nb2O5) under unidirectional sliding (0.03–10m/s; 22°C and 400°C) and oscillation (f=20 Hz, dx=200 mm, 2/50/98% rel. humidity, n=105/106 cycles) will be presented. The microstructure and mechanical properties of the crack-free Nb2O5 are assessed. The tribological data obtained are benchmarked with different NbC grades, ceramics, cermets and thermally sprayed coatings. KW - Friction KW - Wear KW - Nb2O5 KW - Nb12O29 KW - Niobium oxide KW - Strength KW - Modulus KW - High temperatures PY - 2016 U6 - https://doi.org/10.1016/j.wear.2016.02.003 SN - 0043-1648 VL - 352-353 SP - 65 EP - 71 PB - Elsevier B.V. AN - OPUS4-35805 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 - 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 U6 - 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 -