On airborne nano/micro-sized wear particles released from low-metallic automotive brakes

Nanoparticles and cars - analysis of potential sources

“…In April 2011, Kukutschová et al reported a study that focussed on wear particles released from commercially available “low-metallic” automotive brake pads which were subjected to brake dynamometer tests in the experiments [15]. They determined particle size distribution in situ and collected the generated particles for further studies.…”

“…The collected fractions and the original bulk material were analyzed using a multitude of techniques and it was found that airborne wear particles with sizes between 10 nm and 20 μm were released into the air during the experiments. Interestingly, the numbers of nanoparticles (< 100 nm) were by three orders of magnitude larger in comparison to the number of microparticles [15]. …”

“…Concerning the temperature, the authors stated that size distribution of airborne wear particles generated during brake dynamometer simulations representing sub-urban driving segments varies in dependence on temperature of the friction surface [15]. They found that the generation of wear particles smaller than 500 nm was negligible for cold surfaces, while the concentration of nano-sized particles (< 100 nm) gradually increased when the bulk temperature of the rotor approached approximately 300 °C.…”

“…They found that the generation of wear particles smaller than 500 nm was negligible for cold surfaces, while the concentration of nano-sized particles (< 100 nm) gradually increased when the bulk temperature of the rotor approached approximately 300 °C. They also reported that thermal analysis of milled bulk brakes performed in oxidative and inert atmospheres showed a heterogeneous ignition mechanism of carbonaceous particles [15]. The ignition temperature is approximately 300 °C, which correlates with the rotor temperature when the maximum number of finest particles was generated [15].…”

“…They also reported that thermal analysis of milled bulk brakes performed in oxidative and inert atmospheres showed a heterogeneous ignition mechanism of carbonaceous particles [15]. The ignition temperature is approximately 300 °C, which correlates with the rotor temperature when the maximum number of finest particles was generated [15]. …”