The study deals with the friction and wear properties of materials for brake pads. It has been developed in the frame of a research collaboration with ITT Friction Technologies company, who is one of the world leaders in the field of brake pads. The gradual phasing out of asbestos, recognized as carcinogenic materials, pushed pads manufacturers to move away from them, to the purpose to obtain safe components. Such phenomenon resulted in a wide variety of brake pads, each with its peculiar composition: nowadays they numbers more than 15 different constituents and the optimized composition is the result of a very long and complex process, where the real mechanism of contribution from each ingredients is still under study, as well as the mutual influence among constituents. To disentangle the complexity of the phenomena occurring in the contact between pad and disc, the present work focus the attention on the most widespread friction materials. This approach aims to set up a characterization method able to evaluate the effect of the materials composition on friction and wear properties, allowing to obtain a preliminary selection of the raw materials suitable for brake pad application.
The results so far obtained allowed to assess the influence of the materials composition on the friction coefficient (COF) and the wear resistance under different conditions of load, surface contact and temperature. Among the main results, it is noteworthy that pads containing additives having low friction values showed higher COF stability.