Ingenieurwissenschaften und zugeordnete Tätigkeiten
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- Niobium carbide (13)
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Eingeladener Vortrag
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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.
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).
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.
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.
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.
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.
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.