| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 618473 | Wear | 2011 | 12 Pages |
A right selection of filler, its type, shape, size, amount and its compatibility with other co-fillers decide the performance of a friction material (FM) at selected operating condition. Amongst various types of metallic fillers, copper is one of the most important fillers used in such multi-ingredient composite system. It not only enhances the thermal conductivity of composite but also plays an important role in friction and wear mechanism. In spite of these facts, in depth systematic studies on investigation role of copper with varying amount and shape and evaluation as per standard procedure are not documented. Hence, in this work investigation on the role of copper (particles and fibers) in FMs were done. Two series of NAO friction composites with varying amount of copper powder and fibers (0, 10 and 20 wt.%) were developed in laboratory. These were characterized for physical, thermo-physical, chemical and mechanical properties. For tribo-evaluation inertia brake-dynamometer testing which reflects the most realistic performance was selected. The various performance properties like friction, wear, μ sensitivity to load, speed and temperature were studied as per industrial schedule. Overall, it was concluded that inclusion of copper improved all major performance properties. From amount point of view, 10 wt.% consider as best amount and from shape point of view, powder has edge on fibers. Worn surface analysis and wear mechanism are also discussed in details.
Research highlights▶ This article emphasizes on the role of copper (with varying amount and shape) on the performance properties of NAO friction materials (FMs). ▶ Friction and wear properties correlations of laboratory developed FMs containing Cu was evaluated on full scale brake dynamometer. ▶ Inclusion of Cu in FMs affected most of the performance properties in a beneficial way like appreciable increase in magnitude of μ, decrease in μ sensitivity towards pressure–speed, temperature and wear resistance also. ▶ High thermal conductivity and effusivity of the Cu containing composites played an important role in enhancement of the performance properties. ▶ From shape point of view, Cu powder proved best performing then Cu fiber in all aspects viz. performance μ (friction), sensitivity studies (pressure–speed and F&R) and wear behavior. ▶ Transfer of thin coherent Cu enriched film from the tribo-layer on the pad and disc surface was found to be responsible for least damage to the surface.
