Friction and wear studies on the temperature dependence of brake-pad materials containing brass

¹ CNRS, UMR 8107, 59650 Villeneuve d'Ascq, France
² USTL, LML, 59650 Villeneuve d'Ascq, France
³ KU Leuven, Dept. MTM, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
⁴ Univ Lille Nord de France, 59000 Lille, France

Abstract

Brake pad materials for automobile applications are basically polymer matrix composites. Various reinforcing constituents used in brake pads are organic, metallic and ceramic fillers which play among others an important role on the mechanical and thermal properties, and the wear resistance at high temperature. Friction and wear depend on various parameters such as the micro-chemical structure of the pad and of the metallic counter-face, the rotation speed, the pressure, and the contact surface temperature (M.G. Jacko 1983). This latter parameter can be locally as high as 600 up to 1.500 ^∘C depending on the brake type (M.G. Jacko 1983; Blau 2001). Thermal models have been developed to study interface effects at contacting surfaces (Majcherczak, Dufrenoy et al. 2007). Frictional energy can be dissipated through different mechanisms such as oxidation, rise in temperature, formation of wear particles, entropy changes associated to viscoelastic and viscoplastic deformation, and noise generation (Eddoumy, Addiego et al. 2011). Studies of friction brake show that more than 95% of the dissipated energy is transformed into heat (Kasem, Thevenet et al.; Majcherczak, Dufrenoy et al. 2007). Thermal analysis is therefore a primordial step in the study of brake systems since it provides thermo-mechanical properties (Majcherczak, Dufrenoy et al. 2007). The influence of the addition of metallic fibers on the performance of organic friction composites has been investigated using friction tests (Qu, Zhang et al. 2004). Benefits or limitations of the different fibers have been reported, however the issues of thermo-mechanical properties or effect of temperature on friction and wear behavior were not yet investigated (Bijwe, Kumar et al. 2008). No effort was done to correlate the thermo-mechanical and thermal properties with the friction and wear behavior. An important prerequisite is to get a good understanding on how brake materials behave. However, a link between thermal transitions and tribological behavior occurring at different temperatures is still missing.