Effects of Different Kinds of Fibers on Mechanical and Tribological Properties of Brake Friction Materials

The purpose of the present study is to compare the effects of different kinds of fibers on the mechanical and tribological properties (in dry conditions) of a phenolic resin-based friction material. The series of fibers used in the study include rockwool, ceramic, E-glass, and steel wool fibers. The fiber volume fraction in all composites was kept constant at 30%. Tribological studies were performed on a pin-on-disc apparatus at sliding speeds of 3.2-12.8m/s, disc temperatures of 100-350 degrees C, and applied loads of 312.5-625N. Experiments showed that the friction coefficient in general decreased with increasing sliding speed and applied load but increased with increasing disc temperature up to 300 degrees C and then decreased above this temperature. The specific wear rate was found to increase with increasing sliding speed and disc temperature. The highest friction coefficient and specific wear rate were obtained with E-glass and steel wool fiber-reinforced composites, respectively. The wear mechanism was also analyzed by observing the worn surface morphology using a scanning electron microscope (SEM).