Natural fiber reinforced non-asbestos brake friction composites: Influence of ramie fiber on physico-mechanical and tribological properties

The effect of ramie fiber on the physical, tribological and mechanical properties of automotive brake friction composites is studied. Physical and mechanical properties of the composite samples were evaluated as per industrial standards while tribological properties were evaluated in a Chase machine following IS 2472-4 test procedure. The properties such as density, ash content and hardness were found to decrease whereas; porosity, water absorption and compressibility were found to increase with increased ramie fiber content. The tribological outcomes reveal that friction coefficient and friction stability exhibit a decreasing trend whereas fade-%, recovery-%, wear, friction variability and fluctuations show an increasing trend with increased ramie fiber content. The maximum performance coefficient of friction (0.547), maximum friction stability (0.93), lowest fade-% (22.12%), lowest fiction variability (0.33), lowest wear (1.16 g) and least friction fluctuations (0.178) were registered for 5 wt% ramie fiber reinforced composite indicating its excellent tribological performance. The study of worn surfaces reveals that the formation of contact plateaus on the composite surface plays a vital role in controlling the tribological properties of the composites.