Effects of Hybrid Rockwool–Wood Fiber on the Performance of Asbestos-Free Brake Friction Composites

The present study explores the physical-mechanical and tribological properties of hybrid wood fiber and rockwool-reinforced asbestos-free resin-based friction materials. We developed asbestos-free brake friction composites with different contents of hybrid fiber (wood and rockwool fiber) at a total fixed fiber loading of 30%. Then, the developed composites were investigated on the physical, mechanical, and tribological properties according to the industry standards. The results show that, with the increase in wood fiber, the density, hardness, and strength decrease, and the water absorption increases. Meanwhile, rockwool fiber can improve the coefficient of friction and enhance friction stability, while wood fiber has a significant impact on wear resistance. The sample with 5% wood fiber and 25% rockwool fiber presented the best performance in terms of the coefficients of friction, wear rate, and fade–recovery behavior. It provides a new idea for the research of asbestos-free composites.