Analysis of elemental and mineral composition of the car brake pads

Abstract

After the ban of asbestos fibers for brakes manufacturing in mid-90s, composition of brake linings has rapidly changed but there is still a number of possible toxics used (heavy metals, their sulphides, PAHs etc.) [1]. Detailed information on materials used for creating brake pads is not provided by manufacturers. According to the literature [2, 3], brake pads include materials that cause metallic friction (Fe and Fe-Cu oxides), lubricants (graphite and Fe-Sb-Ba-Sn-Mn sulphides) and mineral fibers (Ba, Ca, and Al-silicates) used as fillers. This study aims to investigate elemental and mineral composition of different brake pads including most popular in the country. The information acquired through research is important for emission inventories and toxicological studies. The elemental composition of brake pads was studied using X-ray Fluorescence spectrometry, Scanning Electron Microscope (SEM) and EDS. While X-Ray Diffraction spectrometry (XRD) was used for the identification of mineral composition. After analyzing the results popular element composition is Ca, Fe, S, Al, Ba, Si, Cu and mineral composition (BaSO4, CuO, Fe2O3, ZnO, TiO2). The brake pads have different microstructure, which showed different elements distribution in surface by SEM.