This work focussed on conducting a comparative life cycle assessment (LCA) of novel
environmentally friendly brake rotors for automotive application. The purpose for
this research was to investigate alternative brake rotor solutions to reduce the wear,
emissions and environmental impact from the current uncoated grey cast iron (GCI)
rotor, throughout the whole life cycle, from ’cradle-to-grave’. The less frequent use of
friction brakes within electric vehicles and more stringent legislation have increased the
demand for wear and corrosion resistant materials.
The LCA methodology used the ReCiPe 2016 impact approach with a hierarchist analysis,
including endpoint impact scores for a broader overview of the environmental and human health impacts. The Structured Analysis and Design Technique notation was adapted for LCA applications, simplifying complex systems. A custom Python model was developed to assess the environmental impact of four brake rotor materials: a laser-clad GCI, a Plasma Electrolytic Oxidation (PEO) treated wrought Al, a PEO treated cast Al, and an uncoated GCI rotor as a baseline. All rotors were paired with low-metallic friction materials.
Emission data was collected using a previously developed small-scale test rig operating under WLTP (worldwide harmonised light-vehicle test procedure) cycle conditions. These data were scaled to compare to the impending Euro 7 emission standards, revealing that only coated rotors are likely to meet the new limits. Additional life cycle phase data was collected from industry collaborations and secondary sources. The comparative LCA was streamlined through the omission of identical parts for the different rotor materials.
The study found that coatings or surface treatments can significantly reduce environmental and human health impacts due to their recoating potential and reduced wear rate. Lightweight rotors also offered benefits of reduced fuel consumption and CO2 emissions. Laser-clad GCI, wrought PEO-Al and cast PEO-Al were found to reduce the average endpoint impacts by 37%, 39% and 43%, respectively, compared to the uncoated GCI.
