Filtern
Dokumenttyp
- Beitrag zu einem Tagungsband (2) (entfernen)
Sprache
- Englisch (2)
Referierte Publikation
- nein (2)
Schlagworte
- Artificial third body (1)
- Brake friction materials (1)
- Brake pad formulation (1)
- Friction (1)
- Metal sulphides (1)
- Metal sulphies (1)
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.
A bottom-up approach to study metal sulphides in brake friction materials at higher temperatures
(2017)
The impact of metal sulphides in brake friction materials on the friction behaviour of disc brakes was studied at two different temperatures and in two different atmospheres using a pin-on-disc device with powder supply. Powder mixtures were prepared by using a bottom-up approach, where magnetite is the main component, in which different metal sulphides are mixed in. At 400 °C, the resulting coefficients of friction are higher in air than in nitrogen atmosphere, which can be attributed to the generation of metal oxides and were confirmed by doing thermal analysis.