Recent progress in the research on natural composite brake pads: A comprehensive review

Brake pads are vital parts of automobiles, where tribological properties are prime concern. Usually, asbestos brake pads were used, which were replaced by copper-based in later years. As brake lining materials have evolved, synthetic friction composites were explored as alternatives. Recent works suggest that, natural composites are promising friction material. However, poor thermal conductivity and frictional stability have limited their applications. Surface treatment of fibers and addition of secondary fillers have improved their possibilities. Thus, hybridization of reinforcements has expanded their range of applications. The present article attempts to review various aspects of brake pads and their testing with attention on natural composites. Their properties were studied to conform their ability to meet desired requirements. The article reviews the studies conducted in recent years on various materials properties related to brake pads. The future potential of natural components in the development of friction composite materials for automotive applications is highlighted.