Frictional Characteristics under Corroded Brake Discs

The changes in the humidity as well as temperature difference between the disc brake and surrounding air were identified as the main factors affecting the corrosion built-up. It was important to study the effect of corrosion on braking frictional characteristics. To do so, the corrosion process was first carried out on two different disc brakes labelled as type A and type B where both disc brakes were made from gray cast iron but by different manufacturers. The corrosion effect on the discs was investigated using two different friction material P-1 and P-2. Friction material P-1 was used for the first disc, while friction material P-2 for the second disc. Corrosion process of the disc was carried out in exposed air condition with burnished disc to simulate disc corrosion for a parked vehicle. Both corroded discs were then run and tested with the two different brands of friction materials P-1 and P-2. The change in brake friction coefficients was analysed using a single-ended brake dynamometer. The results showed that the friction materials have their own characteristics that affect the formation of the oxide layer on the disc and consequently, the performance of the frictional force of disc brake system. Friction force was also closely dependent on the removal of the oxide layer, and by the friction film on the burnished disc surface when applying the brake.