Effect of Carbon in Brake Friction Materials on Friction Characteristics

Brake friction materials composed of eight to 20 ingredients in the formulation.Each ingredient has its own function in producing the stable coefficient of friction (COF) and acceptable wear rate.The goal of this work is to study the effect of different carbon volume percentage (vol.%) on the friction characteristics.Three samples were prepared through powder metalurgy process by varying the carbon vol.%.Each sample was subjected to specific gravity, porosity, hardness, chase friction and brake inertia dynamometer tests in accordance with international test procedures.All the entire three samples are sensitive to speed and temperature.COF increased in the early stage of braking.Upon reaching the degradation temperature of polymeric materials, the COF decreased gradually with increasing speed and temperature.The pad thickness loss and rotor roughness decreased with increasing vol.% of carbon in the formulation.Sample B is the best formulation based on the friction characteristics and pad thickness loss.Formulation of sample C is rejected due to lower COF even though has the lowest pad thickness loss.Sample A and sample B will be further analysed and evaluated on-road and reliability performance before can be commercialised and used on the road.