Sepiolite: A new component suitable for 380 ​km/h high-speed rail brake pads

Abstract

To enhance the high-temperature adaptability of copper-based composite materials and C–C/SiC discs, this article innovatively introduces a method of replacing graphite with sepiolite, resulting in the successful fabrication of samples with exceptional mechanical and friction properties. The results reveal that moderate incorporation (less 6%) of sepiolite provides a particle reinforcement effect, resulting in an improvement of mechanical properties. Interestingly, the addition of sepiolite causes a change in the traditional saddle-shaped friction curve due to high temperature lubrication. Meanwhile, the primary advantage of sepiolite lies in its superior abrasion resistance, evident in the increased friction coefficient and altered wear mechanisms with higher sepiolite content. The wear resistance is optimal at 200 ​Km/h (400 ​°C). Particularly, the unique composition of the friction layer (outermost layer: a composite film consisting of B₂O₃, sepiolite, graphite, and metal oxide films; intermediate layer: metal oxide films) plays a pivotal role in improving friction stability. Finally, there are significant optimizations in the GA algorithm, especially GA-GB model has the best prediction effect on the maximum friction temperature.