Significant efforts are currently on going to decrease the non-exhaust emissions from transport sector. As far as the brake system is concerned, these efforts are mostly associated with the research of new friction couples and technological solutions capable to reduce the generation of fine particulate at the brake pad – disc interface. An additional strategy to reduce the environmental impact of brake emissions can arise from: a) increasing the emission particle dimensions; and b) tailoring their chemical composition. Consequently, prior to perform any environmental and toxicological assessment, it is fundamental to characterize the emissions in terms of composition, dimensions, and morphology. At this regard, the work proposes an effective analytical method for the ex-situ characterization of fine particulates (PM10) emitted in air and coarser emissions falling directly to the ground, as obtained by the coupling of Low Steel and NAO friction materials and a reference grey cast iron disc. The Particle Size Distribution (PSD) and chemical composition of the emissions are investigated by the means of a multi-technique protocol based on Scanning Electron Microscopy (SEM), Laser Diffraction (LD), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). Results unveil the complex interplay existing between each typology of investigated friction material and the morphology/chemical composition of the corresponding emitted particulates.

Brembo S.p.A: Dr. Aleesandro Mancini, Ms. Bozhena Tsyupa, Mr. Marco Bandiera, Dr. Matteo Federici, Dr Mara Leonardi, Dr. Federico Bertasi, Dr. Andrea Bonfanti