Effect of micaceous iron oxide on the mechanical and physical properties of eco-friendly Brake Pads

This study investigates the tribological and mechanical performance of copper-free brake pad formulations using powder metallurgy and positive molding techniques. Six sample types were developed, five of which incorporated varying ratios of micaceous iron oxide (MIO) and steel fibers (M۰S۱۵ to M۱۲S۳), while one reference sample (C۹B۶) contained copper and brass chips. The goal was to replace copper-based components with environmentally safer alternatives without compromising performance. Raw materials were homogenized using a ball mill and compacted under controlled pressure and temperature, followed by a multi-stage curing process. Characterization included SEM/EDXS imaging, porosity measurement via the Archimedes method, hardness testing using Rockwell S scale, and shear strength evaluation according to ISIRI ۲۷۹۸. Results showed that increasing MIO content and reducing steel fibers led to lower porosity (from ۷.۱% to ۵.۸%) and higher hardness (from ۷۴ to ۸۰). MIO’s fine, plate-like morphology enhanced particle packing and surface coverage, improving mechanical integrity. Comparisons between copper-free (M۹S۶) and copper-containing (C۹B۶) samples revealed superior wettability and hardness in M۹S۶ due to higher surface energy and Mohs hardness of MIO and steel fibers. Shear strength tests confirmed adequate bonding between the friction material and steel backing plate at both room and elevated temperatures. Overall, the findings support MIO and steel fibers as effective, eco-friendly substitutes for copper in brake pad formulations.