Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (30)
- Vortrag (23)
- Zeitschriftenartikel (17)
- Beitrag zu einem Sammelband (8)
- Posterpräsentation (5)
- Buchkapitel (3)
- Sonstiges (1)
Referierte Publikation
- nein (87) (entfernen)
Schlagworte
- Tribologie (16)
- Friction (14)
- Tribology (11)
- Festschmierstoffe (8)
- Kryotechnik (8)
- Hydrogen (7)
- Hydrogen environment (7)
- MoS2 (7)
- Wear (7)
- PEEK (6)
Organisationseinheit der BAM
- 9 Komponentensicherheit (21)
- 9.5 Tribologie und Verschleißschutz (21)
- 3 Gefahrgutumschließungen; Energiespeicher (3)
- 3.3 Sicherheit von Transportbehältern (2)
- 8 Zerstörungsfreie Prüfung (2)
- 1 Analytische Chemie; Referenzmaterialien (1)
- 1.4 Prozessanalytik (1)
- 2 Prozess- und Anlagensicherheit (1)
- 2.0 Abteilungsleitung und andere (1)
- 2.1 Sicherheit von Energieträgern (1)
Eingeladener Vortrag
- nein (23)
In order to obtain a better understanding of the role of tribofilms during automotive braking, their structures were investigated and the essential features identified.
Next, different ingredient combinations were studied by preparing some model materials with simpler compositions than real tribofilms. A test method was developed for verifying the tribological properties of the model materials and for comparison with results obtained with numerical sliding simulations of such structures. Prerequisites of good brake Performance properties were identified. Although the coefficient of friction could be varied in a wide ränge, smooth sliding conditions could only be achieved with values smaller than 0.4. Tests with artificial third body powders turned out to be useful as screening method for the selection of raw materials for brake pad formulations.
Besides carbon, metal sulphides are used in every standard brake pad formulation as friction stabilisers. In order to investigate their impact, various powder mixtures were tribologically stressed in a pin-on-disc device in order to produce and test artificial third bodies. containing the three main components of a real friction film, namely magnetite, graphite and a metal sulphide of interest. Since the sliding behaviour is influenced by the relative humidity the powder mixtures are tested at low, medium and high moisture levels. The tests revealed that the presence of graphite dominates the friction behaviour as well as the humidity sensitivity.
The powders were prepared by either manual mixing or high energy ball-milling. Interestingly, all ball-milled blends provided coefficients of friction within the desired range for braking, which was attributed to the effect of zirconia particles from wear debris of the milling balls. The zirconia particles prevent the formation of solid lubricant films on the surfaces and support a homogeneous mixture of all constituents of the powder. Optimum brake performance is gained by an optimum combination of solid lubricants and abrasives.
Mittels lasergesteuerter gepulster Vakuumbogentechnologie (Laser-Arc) wurde eine reihe von reinen MoS2-Schichten sowie Kombinationsschichten aus MoS2 und tetraedrischem amorphen Kohlenstoff (ta-C) hergestellt. Mit diesen Schichtvarianten erfolgten tribologische Tests im Vakuum sowie in Atmosphäre. Dabei wurden im Hochvakuum reibungskoeffizienten bis zu 0,005 gemessen. Durch die Verwendung einer ta-C unterschicht konnte eine Lebensdauer von über 5×105 Lastzyklen erreicht werden. Zudem erwies sich diese unterschicht als vorteilhaft für das tribologische Verhalten der MoS2/ta-C Schichten unter atmosphärischen Bedingungen. -------------------------------------------------------------------------------------------------------------------------------------------
A series of MoS2 and combined MoS2/ta-C coatings were prepared by lasercontrolled arc evaporation (Laser-Arc) in order to study the tribological coating behaviour under vacuum and atmospheric conditions. Very low friction coefficients down to 0.005 were measured under high vacuum. By using a ta-C underlayer beneath the MoS2 a increased lifetime up to 5×105 load cycles could be obtained. Also under atmospheric conditions the underlayer had a beneficial effect on coating performance.
Tribologisches Verhalten der Werkstoffpaarung Polymerverbundwerkstoff/Stahl bei tiefen Temperaturen
(2005)
Die Reibeigenschaften von PEEK-Materialien gegen Stahlscheiben wurden in Luft, Vakuum und Wasserstoffumgebung untersucht. Die Ergebnisse zeigen, dass reines PEEK umgebungsabhängig ist und die Desorption von Gasen im Vakuum zu hohen Verschleißraten führt. Die niedrigsten Verschleißraten sowohl in Vakuum als auch in einer Wasserstoffumgebung erzielen TiO2-Partikel. Ferner treten chemische Prozesse in den Materialien und im Tribokontakt auf und interagieren miteinander.
The tribological characteristics of pure and graphite filled polymers were investigated in gaseous hydrogen at ambient temperatures and in LH2 at -253°C. It could be shown that the tribological properties of PI and PEEK materials is related to the formation of a transfer film. The influence of both hydrogen and cryogenic temperatures will be discussed in the presentation.
The development of hydrogen technologies is a key strategy to reduce greenhouse gas emission worldwide. Power-to-Gas is a challenging solution, in which hydrogen and methane can be used in mobility, industry, heat supply and electricity generation applications. This presentation deals with the tribological behaviour of polymer materials in hydrogen and methane, both in gas and in liquefied form.
Aim of the investigation is to characterize selected PEEK-composites in vacuum environment. Oscillating sliding friction was investigated with a pin-on-disc configuration in high vacuum (10-5 mbar) at room temperature, -40 °C, +100 °C and +160 °C. The contact pressure was 1 MPa and 7 MPa respectively , the maximum sliding velocity 0.1 m/s. Furthermore, tests in ultra high vacuum (10-9 mbar) were carried out with flat and spherical pins at 1 MPa and 60 MPa respectively. Among the tested materials MoS2 filled PEEK shows the best tribological performance in vacuum. Particularly, in the lower temperature range and at higher loads the friction behaviour is improved by MoS2 content.