The Influence of the Addition of Different Kinds of Slags on the Friction and Emission Behavior of a Commercially Employed Friction Material Formulation

Keeping sustainability and the circular economy in mind, numerous studies have been conducted on the feasibility of the utilization of industrial wastes in friction material formulations for braking applications. One such highly produced waste is slags from blast furnaces. The present work focuses on the friction, wear, and emissions behavior of a commercially employed friction material formulation observing the inclusion of three kinds of slags. Two types of slags were obtained from a blast furnace; the difference was the cooling method. The third type of slag was collected from a basic oxygen steel furnace. The prepared samples were tested in the form of pins on a pin on disc equipment at 1.51 m/s, 1 MPa, and ambient conditions to replicate a mild braking scenario. Irrespective of the type of slag, the addition of the wastes observed either a decrease or similar emissions when compared to the virgin formulation. The friction and wear were in the range comparable to that of the reference composition; the CoF for slag specimens ranged between 0.49-0.51 compared to 0.45 for the reference composition. On the other hand, by inspection of the worn surfaces of the pins, it was seen that the slag-containing specimens had compact and expansive secondary contact plateaus with the inclusion of slag particles in their composition. Through this preliminary analysis, the possibility of the utilization of different slags is highlighted, especially in an already implemented commercial formulation, paving the path for further testing and validation.