The current study deals with the surface modification of gray cast iron (GCI) brake discs through a laser cladding process using a martensitic steel cladding material containing MnS as a solid lubricant. The technique addresses the importance of recycling the vehicular brake disc after its useful lifespan and improving the brake disc's tribological properties. The tribological properties of the coated disc were evaluated using an eco-friendly copper-free friction material through pin-on-disc (PoD) tribology tests. The microstructural analysis indicated that the coating is well bonded to GCI substrate, has a thickness of about 2.5 mm. The XRD and SEM analysis indicated that the coating consisted of martensite, austenite, chromium carbides, and MnS particle dispersion within the dendritic areas. The PoD test results showed that introducing MnS solid lubricant in the composition of the martensitic cladding materials slightly diminished the coefficient of friction. The results of this research might be useful in the development of protective coatings for brake discs even in the perspective of the relevant emissions of particulate matter.

University of Trento: Mr. Hossein Rajaei, Prof. Cinzia Menapace, Prof. Stefano Gialanella, Prof. Giovanni Strafellini