The Corrosion of grey cast iron rotors impacting the production of braking systems is an important issue in the automotive sector. In particular, short term corrosion of the grey cast iron discs can lead to undesired corrosion attack, while long term corrosion might imply comfort and durability of the braking system. Moreover, corrosion attack of the gray cast iron might cause stiction phenomena between the braking pad and disc leading to possible damage of the pad. In this context, the introduction of the Electric Vehicles could stress more the situation due to the fact that the regeneratives system will suppress an important amount of the hydraulic brake applications. This fact is leading to an empooring the rust cleanabilty capability of the rotor in those brake systems. Therefore is important to develop friction materials able to make a good rotor corrosion cleanibitly in this new dynamic brake conditions. In this work, will be presented the rust removal conditions and simulations in a tribometer compared with a brake dynamometer. The tribometer allows to study in laboratory scale the formation and cleanability dynamics of the rust and the influence of the third body layer on the rotors surface. This scale of study allows to study more on depth the dynamics of the rust formation and the removal simulating phenomena that happends on the field. Moreover, this tribometer study could highlight the different capability of rust removal poropensity for selected pads materials with different composition. The surface analysis of disc and pad samples are investigated by FIB-SEM-EDXS, Surface profilometer and optical analysis in order to highlight mechanisms involved in corrosion removal process.

Mr. Agusti Sin, Materials & Process Innovation, ITT Friction Technologies