A pin-on-disc tribometer study of disc brake contact pairs with respect to wear and airborne particle emissions

In the EU, PM10 from the wear of disc brakes can contribute up to 50% of the total non-exhaust emissions from road transport. The wear originates from the contact surfaces of the friction material and the disc. One possible way to decrease PM10 emissions is to change the materials of the contact pair in terms of composition and coatings. The wear and particle emissions of three novel friction material formulations, one novel disc formulation, one disc WC/CoCr coating realized with the HVOF technique, and one disc surface treatment realized by a nitriding process, were investigated. Pin-on-disc tests were run to rank the novel materials in terms of specific wear rate and particle number and mass rate. The results show that it is possible to achieve a reduction in particle emissions of up to 50% by changing the materials of the contact pair.