Tribological performance of volcanic rock (perlite)-filled phenolic-based brake friction composites

The present work investigated the influence of perlite on the tribological properties of phenolic-based brake friction composites. The composites were manufactured by mechanical mixing and compression moulding at different perlite loadings as 0%, 5%, 10% and 15% by weight and tribo evaluated following European regulations. Among the evaluated tribological properties, the highest coefficient of friction (0.430), the lowest fade (16.74%) and friction fluctuations (0.221) with the least friction variability (0.434) were registered in the composite with 5 wt.% perlite content. The recovery performance increased with perlite addition and remains highest (119.85%) in the composite with 15 wt.% perlite content. The friction stability, maximum disc temperature rise and wear resistance of the composites decreased with increased perlite content. The worn surface investigations revealed that the formation of contact plateaus largely influences such composites' tribological performance.