Automotive non-exhaust emissions, such as brake- and tyre wear are of rising interest, since they will be regulated for the first time with the EURO 7 regulation. While the majority of the particle mass of these abrasion derived particles is between 1 and 10 µm, a considerable percentage of the particle number is also generated in the nanoparticle range. These particles can penetrate deep into the lungs, where they deposit in the alveoli and eventually reach the bloodstream via the blood-air barrier. 

In this study the chemical and physical properties of brake wear particles emitted from a newly developed EURO 7 brake dyno were characterized. Non-asbestos organic brake pads (NAO), as well as low metallic brake pads (LM), were compared regarding emitted particle mass (PM), particle numbers (PN), as well as their size and morphology utilizing the WLTP bake cycle on a newly build custom brake dyno. 

Quartz fibre filters wear extracted and analysed for polycyclic aromatic hydrocarbons by GC-MS/MS to see if high local temperatures leads to generation of such carcinogenic substances at the brake interface due to thermal degradation of the polymer binding matrix of the brake pads.

Inductively coupled plasma mass spectrometry (ICP-MS) was used for bulk analysis of heavy metals, in combination with a scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy detector (SEM/EDX) for individual elemental particle spectra, to give a broader understanding of the highly metallic nature of brake wear derived particles. SEM micrographs of brake particles, showed rough edges commonly found for abrasion derived particles, while the elemental compositions obtained via ICP-MS showed large differences in the metallic content of NAO and LM pads, suggesting different impact on environment and human health. 

Lastly a co-culture cell model consisting of human bronchial epithelial cells from the A549 and CALU-3 cell lines were exposed to the aerosol at the so-called Air/Liquid interface to investigate the toxicity of PM2.5 generated by the two analysed brake pads.

The future of Mobility is closely related to the fight against climate change, through the limitation of emissions of all kinds to conclude with the complete electrification of the mobile fleet. In the context of the Green Deal and the objectives of "carbon neutrality" and "zero pollution", the European Commission has committed to reducing current emission limits, from all sources. Brake wear is a significant contributor to respirable particulate matter (PM10 aerodynamic diameter less than 10 µm), particularly in areas with high traffic density and frequent braking. How far emission regulation and electrification may transform the friction industry is still to see. The application of surface technology to the rotor can technically solve this problem and several technologies are being evaluated. But changes in the rotor material induce changes in the response of the friction material, and those can be different depending on the type of friction material and the coating material and technique. In this conference we will be showing some of the changes in tribochemistry and friction response related to the use of coatings, with different carbide coatings. When a hard coating is applied on the rotor, the traditional pad/rotor wear mechanism is affected. The transfer of material from the rotor (in form of iron oxide) is minimized and can even be dismissed. Abrasive wear of the friction material then become the main wear mechanism of the new friction pair. Then the raw materials used in the pad have a big influence on this behaviour. In a joint research work by Rimsa, Quartz and Lapinus, tribological data have been obtained through simulated SAE standard tests by using brake pad screening tribometer, and Tribochemistry was studied by SEM-EDS. We expect to contribute with this work to further build a deep knowledge of how coating parameters may affect the friction behavior of friction materials, allowing the community to find new ways to use more sustainable materials for wear resistant coating.

Base metals — such as iron ore, copper, aluminium and nickel — are the lifeblood of global industrial production and construction. Shaped by shifts in supply and demand, they are a valuable weathervane of change in the world economy. While attracting less attention than oil prices, metal prices have also been fluctuating strongly since the end of 2003. Metal prices were relatively stable between 1995 and the end of 2003, when demand for metals shifted from advanced economies in the West to emerging markets in the East. The addition of sulfide to the friction material modifies the tribochemistry of the pad/rotor interface, reducing the stick and slip effect, providing a more stable coefficient of friction at high temperatures and reducing the wear. Innovamat is a new Brand born from the collaboration of two well renowned manufacturers of additives for friction materials, Quartz and Rimsa, Rimsa and Quartz, taking advantage of the synergies in between the capabilities of both companies to provide innovative solutions through innovative products to the friction materials industry, and beyond. Our first contribution to those challenges is a comprehensive catalogue of SYNTHETIC SULFIDES designed to replace the LME dependent sulfides, like Tin Sulfides. Discover how our innovative approach to synthetic sulfides contributes to keeping the tribochemistry in the rotor and the pad, providing the same benefit than traditional sulfides based on Tin, Copper or Antimony.