Waste and natural fiber based automotive brake composite materials: Influence of slag and coir on tribological performance

Abstract Physical, mechanical, and tribological properties of automotive brake friction materials were investigated to study the influence of various slag waste and coir fiber combinations. The friction composites were manufactured by mechanical mixing and compression molding at varying slag waste (45%, 50%, 55%, and 60%, by weight) and coir fiber (5%, 10%, 15%, and 20%, by weight) loading. The density, hardness, shear strength, and ash content decreased while porosity and compressibility of the composites increased for decreasing slag waste with a simultaneous increase in coir fiber content. The tribological properties of the manufactured composites were evaluated on a Krauss machine by following the ECE R‐90 standard. The highest friction (0.396), lowest fade (15.40%), and lowest friction fluctuations (0.101) were recorded for the composite having 60 wt% slag waste and 5 wt% coir fiber content. In contrast, recovery performance remains highest (131.80%) in the composite with 45 wt% slag waste and 20 wt% coir fiber content. Besides, the wear of the composites was found to increase with increased coir fiber content. Moreover, the composites' worn surfaces were studied using scanning electron microscopy to understand the mechanisms responsible for the surface damage and how slag waste and coir fiber combinations would affect such friction composite materials' friction and wear performance.