Eco-Friendly Brake Pad Materials: A Comprehensive Review for Automotive Applications

Abstract

Brake pads are critical to vehicle safety, yet conventional materials such as asbestos and copper have been linked to severe health and environmental hazards, prompting global regulatory bans. This review synthesizes findings from recent studies (2022–2026) examining the use of bio-based and agro-waste materials—including coconut shells, palm kernel shells, bamboo fibers, molluscan shell powders, and sawdust—as eco-friendly substitutes in brake pad composites. These natural fiber and particulate reinforcements consistently deliver friction coefficients of 0.35–0.49, low specific wear rates, and thermal stability up to 600 °C, while offering advantages of lower density, cost-effectiveness, and biodegradability. The paper further reviews the role of friction modifiers (carbon fiber, zeolite, MoS₂, PDMS), copper-free metallic alternatives (steel fiber, aluminum), and process optimization. Evaluation methodologies including CHASE dynamometer testing, SEM/EDX analysis, finite element simulation, and machine learning-aided formulation are discussed. Key challenges such as moisture sensitivity, fiber agglomeration, and scale-up difficulties are identified, along with future directions encompassing AI-driven design, hybrid formulations, and bio-resin systems. These advances position eco-friendly brake pads as viable replacements for conventional materials in next-generation automotive and electric vehicle platforms.